Imaging lens and imaging apparatus

ABSTRACT

An imaging lens includes a positive first lens group and a second lens group, which are continuous in order from the position closest to the object side, as lens groups. During focusing, the distance between the first lens group and the second lens group changes. A stop is disposed closer to the image side than a lens which is second from the object side. A combined refractive power of all lenses closer to the object side than the stop is positive. The imaging lens includes an LA positive lens and an LB positive lens that satisfy a predetermined conditional expression at a position closer to the object side than the stop. An Abbe number of the LB positive lens is the maximum among Abbe numbers of all positive lenses closer to the object side than the stop.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 toJapanese Patent Application No. 2020-012799, filed on Jan. 29, 2020 andJapanese Patent Application No. 2020-219164, filed on Dec. 28, 2020, thecontents of which are hereby expressly incorporated herein by referencein their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to an imaging lens and an imagingapparatus.

2. Description of the Related Art

Conventionally, as an imaging lens that can be used in an imagingapparatus such as a digital camera, imaging lenses described inJP2015-141384A and JP2016-173398A below are known.

SUMMARY OF THE INVENTION

In recent years, there has been a demand for a suitable imaging lenswhich has a small F number and in which various aberrations aresatisfactorily corrected.

The present disclosure has been made in consideration of theabove-mentioned situation, and its object is to provide a suitableimaging lens, which has a small F number and in which variousaberrations are satisfactorily corrected, and an imaging apparatuscomprising the imaging lens.

According to an aspect of the present disclosure, there is provided animaging lens comprising, as lens groups, successively in order from aposition closest to an object side to an image side: a first lens groupthat has a positive refractive power; and a second lens group that has arefractive power, in which during focusing, a distance between the firstlens group and the second lens group changes, and mutual distancesbetween all lenses in the first lens group and mutual distances betweenall lenses in the second lens group are constant, a stop is disposedcloser to the image side than a lens which is second from the objectside, a combined refractive power of all lenses closer to the objectside than the stop is positive, at least one LA positive lens and atleast one LB positive lens are provided closer to the object side thanthe stop, an Abbe number of the LB positive lens based on a d line is amaximum of Abbe numbers of all the positive lenses closer to the objectside than the stop based on the d line, a refractive index of the LApositive lens at the d line is NdA, an Abbe number of the LA positivelens based on the d line is νdA, and assuming that the Abbe number ofthe LB positive lens based on the d line is νdB, Conditional Expressions(1), (2), and (3) are satisfied.

1.86<NdA<2.2  (1)

10<νdA<35  (2)

57<νdB<105  (3)

It is preferable that the imaging lens according to the aspect of thepresent disclosure satisfies at least one of Conditional Expression(1-1), (2-1), or (3-1).

1.88<NdA<2.15  (1-1)

13.5<νdA<31  (2-1)

62<νdB<92  (3-1)

It is preferable that the first lens group includes at least twopositive lenses and at least two negative lenses.

It is preferable that the second lens group includes at least twopositive lenses and at least two negative lenses.

It is preferable that the first lens group remains stationary withrespect to an image plane and the second lens group moves duringfocusing.

It is preferable that only one lens group moves during focusing. In thatcase, it is preferable that the lens group that moves during focusing isonly the second lens group.

It is preferable that the first lens group includes at least twonegative lenses. Assuming that an average value of Abbe numbers of twonegative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, it is preferable that the imaging lens of the present disclosuresatisfies Conditional Expression (4), and it is more preferable that theimaging lens satisfies Conditional Expression (4-1).

15<νdn1<28  (4)

16<νdn1<25  (4-1)

It is preferable that during focusing, the first lens group remainsstationary with respect to an image plane, and the first lens groupincludes at least one LA positive lens.

In the imaging lens according to the aspect of the present disclosure,assuming that a sum of a distance on an optical axis from a lens surfaceclosest to the object side to a lens surface closest to the image sideand a back focal length at an air-converted distance in a state where anobject at infinity is in focus is TL, an F number of the imaging lens inthe state where the object at infinity is in focus is FNo, and a focallength of the imaging lens in the state where the object at infinity isin focus is f, it is preferable that Conditional Expression (5) issatisfied.

1.5<TL×FNo/f<5  (5)

It is preferable that the imaging lens according to the aspect of thepresent disclosure comprises, in order from an object side to an imageside, as lens groups, only two lens groups consisting of the first lensgroup that remains stationary with respect to an image plane duringfocusing and the second lens group that moves during focusing, orcomprises, in order from the object side to the image side, as lensgroups, only three lens groups consisting of the first lens group thatremains stationary with respect to the image plane during focusing, thesecond lens group that moves during focusing, and a third lens groupthat consists of two or less lenses and remains stationary with respectto the image plane during focusing.

The second lens group may be a lens group having a positive refractivepower.

It is preferable that the first lens group includes at least threenegative lenses.

It is preferable that the second lens group includes at least twopositive lenses and at least three negative lenses.

The imaging lens according to the aspect of the present disclosure maybe configured such that, in a case where one lens component is onesingle lens or one cemented lens, among the lens component closest tothe object side and the lens component which is second from the objectside, one lens component has a negative refractive power and the otherlens component has a positive refractive power, and on-axis ray emittedfrom a lens surface closest to the image side in the one lens componenthaving a negative refractive power to the image side in a state wherethe object at infinity is in focus is divergent light.

It is preferable that at least one of the lens closest to the objectside or a lens which is second from the object side is a negative lensof which the object side lens surface has a concave shape.

It is preferable that the lens closest to the object side is a negativelens.

It is preferable that the imaging lens according to the aspect of thepresent disclosure comprises, successively in order from the positionclosest to the object side: a single lens that has a negative refractivepower, a single lens that has a positive refractive power, and a singlelens that has a positive refractive power.

It is preferable that the object side lens surface of the lens closestto the object side has a concave shape.

It is preferable that the imaging lens according to the aspect of thepresent disclosure comprises at least one LC positive lens closer to theobject side than the stop, in which the LC positive lens is a positivelens having a maximum or second largest Abbe number based on the d lineamong all positive lenses closer to the object side than the stop, andassuming that the Abbe number of the LC positive lens based on the dline is νdC, Conditional Expression (6) is satisfied.

57<νdC<102  (6)

Assuming that a minimum value of refractive indexes of all positivelenses closer to the object side than the stop at the d line is Ndfm, itis preferable that the imaging lens according to the aspect of thepresent disclosure satisfies Conditional Expression (7).

1.46<Ndfm<1.72  (7)

It is preferable that the stop is disposed in a lens group which remainsstationary with respect to an image plane during focusing, or the stopis disposed between the lens groups.

It is preferable that the stop is disposed between the first lens groupand the second lens group, and the first lens group and the stop remainstationary with respect to an image plane and the second lens groupmoves during focusing.

It is preferable that the second lens group moves during focusing, andthe number of lenses included in the second lens group is preferably 7or less, more preferably 6 or less, and yet more preferably 5 or less.

The number of lenses disposed closer to the object side than the stop ispreferably 8 or less, more preferably 7 or less.

The number of lenses included in the imaging lens according to theaspect of the present disclosure is preferably 13 or less, and morepreferably 12 or less.

The imaging lens according to the aspect of the present disclosurecomprises at least two positive lenses closer to the image side than thestop, in which assuming that an average value of the refractive indexesof all positive lenses closer to the image side than the stop at the dline is Ndpr, it is preferable that Conditional Expression (8) issatisfied.

1.77<Ndpr<2.15  (8)

It is preferable that during focusing, the second lens group moves, andthe second lens group includes at least one positive lens, and assumingthat an average value of refractive indexes of all the positive lensesin the second lens group at the d line is Nd2p, it is preferable thatthe imaging lens according to the aspect of the present disclosuresatisfies Conditional Expression (9).

1.7<Nd2p<2.2  (9)

It is preferable that the second lens group moves during focusing, andthe second lens group includes at least two cemented lenses.

It is preferable that three positive lenses are successively arranged inthe first lens group. It is more preferable that four positive lensesare successively arranged in the first lens group.

Assuming that a focal length of the first lens group is f1, and a focallength of the imaging lens in a state where an object at infinity is infocus is f, it is preferable that the imaging lens according to theaspect of the present disclosure satisfies Conditional Expression (10).

0.5<f1/f<3.5  (10)

Assuming that a maximum half angle of view of the imaging lens in astate where an object at infinity is in focus is ω max, and an F numberof the imaging lens in the state where the object at infinity is infocus is FNo, it is preferable that the imaging lens according to theaspect of the present disclosure satisfies Conditional Expression (11).

1.8<1/{tan(ω max)×FNo}<4.5  (11)

It is preferable that the second lens group moves during focusing.Assuming that a focal length of the second lens group is f2, and a focallength of the imaging lens in a state where the object at infinity is infocus is f, it is preferable that the imaging lens according to theaspect of the present disclosure satisfies Conditional Expression (12).

0.3<|f2|/f<2.2  (12)

Assuming that a focal length of the first lens group is f1, and a focallength of the second lens group is f2, it is preferable that the imaginglens according to the aspect of the present disclosure satisfiesConditional Expression (13).

1<f1/f2<5  (13)

It is preferable that the second lens group moves during focusing.Assuming that a lateral magnification of the second lens group in thestate where an object at infinity is in focus is β2, and a combinedlateral magnification of all lenses closer to the image side than thesecond lens group in a state where the object at infinity is in focus isβr in a case where a lens is disposed closer to the image side than thesecond lens group, and βr is set to 1 in a case where no lens isdisposed closer to the image side than the second lens group, it ispreferable that the imaging lens according to the aspect of the presentdisclosure satisfies Conditional Expression (14).

0.3<|(1−β2²)×βr ²|<1.5  (14)

Assuming that a distance on an optical axis from a lens surface closestto the object side to the stop in a state where an object at infinity isin focus is Tf, and a sum of a distance on an optical axis from a lenssurface closest to the object side to a lens surface closest to theimage side and a back focal length at an air-converted distance in thestate where the object at infinity is in focus is TL, it is preferablethat the imaging lens according to the aspect of the present disclosuresatisfies Conditional Expression (15).

0.2<Tf/TL<0.65  (15)

It is preferable that the first lens group includes, successively inorder from the position closest to the object side, a first unit whichhas a negative refractive power and a second unit which is separatedfrom the first unit by a maximum air distance on an optical axis in thefirst lens group and has a positive refractive power, and the secondunit consists of one single lens or one cemented lens. Assuming that afocal length of the imaging lens in a state where an object at infinityis in focus is f, and a combined focal length of all lenses closer tothe image side than the second unit of the imaging lens in the statewhere the object at infinity is in focus is fm, it is preferable thatthe imaging lens according to the aspect of the present disclosuresatisfies Conditional Expression (16).

0.7<f/fm<0.98  (16)

In a case where the first lens group includes the first unit and thesecond unit, it is preferable that the first unit consists of onenegative lens, and the second unit consists of one positive lens.

Assuming that a partial dispersion ratio between a g line and an F lineof the LA positive lens is θgFA, it is preferable that the imaging lensaccording to the aspect of the present disclosure satisfies ConditionalExpression (17).

0.01<θgFA+0.00162×νdA−0.64159<0.06  (17)

Assuming that a partial dispersion ratio of the LB positive lens betweena g line and an F line is θgFB, it is preferable that the imaging lensaccording to the aspect of the present disclosure satisfies ConditionalExpression (18).

0.01<θgFB+0.00162×νdB−0.64159<0.05  (18)

It is preferable that the first lens group includes at least twonegative lenses. Assuming that an average value of Abbe numbers of twonegative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, and an average value of partial dispersion ratios of two negativelenses between a g line and an F line is θgFn1 where the two negativelenses are selected from the negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, it is preferable that the imaging lens according to the aspect ofthe present disclosure satisfies Conditional Expression (19).

0.01<θgFn1+0.00162×νdn1−0.64159<0.05  (19)

The imaging apparatus of the present disclosure includes the imaginglens according to the aspect of the present disclosure.

In the present specification, it should be noted that the terms“consisting of ˜” and “consists of ˜” mean that the lens may include notonly the above-mentioned elements but also lenses substantially havingno refractive powers, optical elements, which are not lenses, such as astop, a filter, and a cover glass, and mechanism parts such as a lensflange, a lens barrel, an imaging element, and a camera shakingcorrection mechanism.

In addition, the term “˜ group that has a positive refractive power” inthe present specification means that the group has a positive refractivepower as a whole. Likewise, the “˜ group having a negative refractivepower” means that the group has a negative refractive power as a whole.“A lens having a positive refractive power”, “a lens having a positivepower”, and “a positive lens” are synonymous. “A lens having a negativerefractive power”, “a lens having a negative power”, and “a negativelens” are synonymous. The term “a single lens” means one lens that isnot cemented.

The “lens group” is not limited to a configuration in which the lensgroup consists of a plurality of lenses, but the lens group may consistof only one lens. A compound aspheric lens (a lens which is integrallycomposed of a spherical lens and a film having an aspheric shape formedon the spherical lens, and functions as one aspheric lens as a whole) isnot be considered as a cemented lens, and is treated as a single lens.Unless otherwise specified, the sign of the refractive power, thesurface shape of the lens surface, and the radius of curvature of a lensincluding an aspheric surface are considered in the paraxial region.Regarding the sign of the radius of curvature, the sign of the radius ofcurvature of the surface convex toward the object side is positive andthe sign of the radius of curvature of the surface convex toward theimage side is negative.

In the present specification, the term “whole system” means “imaginglens”. In the present specification, the phrase “closest to the objectside in the whole system” is also simply referred to as the “closest tothe object side”. Further, the phrase “in order from the object side tothe image side” regarding the arrangement order is also simply referredto as “in order from the object side”. The term “focal length” used in aconditional expression is a paraxial focal length. The value of “FNo”used in the conditional expression is the value of the open F number.The term “back focal length” is the distance on the optical axis fromthe lens surface closest to the image side to the image side focalposition of the imaging lens. The values used in Conditional Expressionsare values in the case of using the d line as a reference in a statewhere the object at infinity is in focus. The partial dispersion ratioθgF between the g line and the F line of a certain lens is defined byθgF=(Ng−NF)/(NF−NC), where Ng, NF, and NC are the refractive indexes ofthe lens at the g line, the F line, and the C line. The “d line”, “Cline”, “F line”, and “g line” described in the present specification areemission lines. The wavelength of the d line is 587.56 nm (nanometers)and the wavelength of the C line is 656.27 nm (nanometers), thewavelength of F line is 486.13 nm (nanometers), and the wavelength of gline is 435.84 nm (nanometers).

According to the present disclosure, it is possible to provide asuitable imaging lens, which has a small F number and in which variousaberrations are satisfactorily corrected, and an imaging apparatuscomprising the imaging lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration and rays of animaging lens (an imaging lens of Example 1) according to an embodiment.

FIG. 2 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 1.

FIG. 3 shows lateral aberration diagrams of the imaging lens accordingto Example 1.

FIG. 4 is a cross-sectional view showing a configuration and rays of animaging lens of Example 2.

FIG. 5 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 2.

FIG. 6 shows lateral aberration diagrams of the imaging lens accordingto Example 2.

FIG. 7 is a cross-sectional view showing a configuration and rays of animaging lens of Example 3.

FIG. 8 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 3.

FIG. 9 shows lateral aberration diagrams of the imaging lens accordingto Example 3.

FIG. 10 is a cross-sectional view showing a configuration and rays of animaging lens of Example 4.

FIG. 11 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 4.

FIG. 12 shows lateral aberration diagrams of the imaging lens accordingto Example 4.

FIG. 13 is a cross-sectional view showing a configuration and rays of animaging lens of Example 5.

FIG. 14 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 5.

FIG. 15 shows lateral aberration diagrams of the imaging lens accordingto Example 5.

FIG. 16 is a cross-sectional view showing a configuration and rays of animaging lens of Example 6.

FIG. 17 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 6.

FIG. 18 shows lateral aberration diagrams of the imaging lens accordingto Example 6.

FIG. 19 is a cross-sectional view showing a configuration and rays of animaging lens of Example 7.

FIG. 20 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 7.

FIG. 21 shows lateral aberration diagrams of the imaging lens accordingto Example 7.

FIG. 22 is a cross-sectional view showing a configuration and rays of animaging lens of Example 8.

FIG. 23 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 8.

FIG. 24 shows lateral aberration diagrams of the imaging lens accordingto Example 8.

FIG. 25 is a cross-sectional view showing a configuration and rays of animaging lens of Example 9.

FIG. 26 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 9.

FIG. 27 shows lateral aberration diagrams of the imaging lens accordingto Example 9.

FIG. 28 is a cross-sectional view showing a configuration and rays of animaging lens of Example 10.

FIG. 29 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 10.

FIG. 30 shows lateral aberration diagrams of the imaging lens accordingto Example 10.

FIG. 31 is a cross-sectional view showing a configuration and rays of animaging lens of Example 11.

FIG. 32 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 11.

FIG. 33 shows lateral aberration diagrams of the imaging lens accordingto Example 11.

FIG. 34 is a cross-sectional view showing a configuration and rays of animaging lens of Example 12.

FIG. 35 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 12.

FIG. 36 shows lateral aberration diagrams of the imaging lens accordingto Example 12.

FIG. 37 is a cross-sectional view showing a configuration and rays of animaging lens of Example 13.

FIG. 38 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 13.

FIG. 39 shows lateral aberration diagrams of the imaging lens accordingto Example 13.

FIG. 40 is a cross-sectional view showing a configuration and rays of animaging lens of Example 14.

FIG. 41 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 14.

FIG. 42 shows lateral aberration diagrams of the imaging lens accordingto Example 14.

FIG. 43 is a cross-sectional view showing a configuration and rays of animaging lens of Example 15.

FIG. 44 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 15.

FIG. 45 shows lateral aberration diagrams of the imaging lens accordingto Example 15.

FIG. 46 is a cross-sectional view showing a configuration and rays of animaging lens of Example 16.

FIG. 47 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 16.

FIG. 48 shows lateral aberration diagrams of the imaging lens accordingto Example 16.

FIG. 49 is a cross-sectional view showing a configuration and rays of animaging lens of Example 17.

FIG. 50 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 17.

FIG. 51 shows lateral aberration diagrams of the imaging lens accordingto Example 17.

FIG. 52 is a cross-sectional view showing a configuration and rays of animaging lens of Example 18.

FIG. 53 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 18.

FIG. 54 shows lateral aberration diagrams of the imaging lens accordingto Example 18.

FIG. 55 is a cross-sectional view showing a configuration and rays of animaging lens of Example 19.

FIG. 56 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 19.

FIG. 57 shows lateral aberration diagrams of the imaging lens accordingto Example 19.

FIG. 58 is a cross-sectional view showing a configuration and rays of animaging lens of Example 20.

FIG. 59 shows spherical aberration diagrams, astigmatism diagrams,distortion diagrams, lateral chromatic aberration diagrams of theimaging lens of Example 20.

FIG. 60 shows lateral aberration diagrams of the imaging lens accordingto Example 20.

FIG. 61 is a perspective view of the front side of an imaging apparatusaccording to an embodiment.

FIG. 62 is a perspective view of the rear side of an imaging apparatusaccording to an embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. FIG. 1 is a diagramshowing a configuration in a cross section including an optical axis Zof an imaging lens according to an embodiment of the present disclosure.The example shown in FIG. 1 corresponds to the imaging lens of Example 1to be described later. FIG. 1 shows a state where the object at infinityis in focus, and shows on-axis rays 2 and rays with the maximum angle ofview 3, where the left side is the object side and the right side is theimage side.

FIG. 1 shows an example in which an optical member PP having a parallelplate shape is disposed between an imaging lens and an image plane Simunder assumption that the imaging lens is applied to the imagingapparatus. The optical member PP is a member assumed to include atvarious filters, a cover glass, and/or the like. The various filtersinclude, for example, a low pass filter, an infrared cut filter, and afilter that cuts a specific wavelength region. The optical member PP hasno refractive power, and the optical member PP may be configured to beomitted.

The imaging lens according to the present disclosure is a single-focuslens, and comprises, successively in order from the position closest tothe object side to the image side along the optical axis Z, a first lensgroup G1 having a positive refractive power, and a second lens group G2having a refractive power, as lens groups. Further, an aperture stop Stis disposed closer to the image side than the lens which is second fromthe object side. By making the refractive power of the first lens groupG1 positive, there is an advantageous in shortening the total lenslength.

The imaging lens of the present disclosure may further comprise a lensgroup closer to the image side than the second lens group G2. It shouldbe noted that the term “lens group” in the present specification refersto a part including the at least one lens, which is a constituent partof the imaging lens and is divided by an air distance that changesduring focusing. During focusing, the lens groups move or remainstationary, and the mutual distance between the lenses in one lens groupdoes not change.

As an example, the imaging lens shown in FIG. 1 consists of a first lensgroup G1, an aperture stop St, a second lens group G2, and a third lensgroup G3 in order from the object side. Further, the aperture stop Stshown in FIG. 1 does not indicate a shape thereof, but indicates aposition thereof on the optical axis. In the imaging lens of FIG. 1, asan example, the first lens group G1 consists of seven lenses L1 a to L1g in order from the object side, and the second lens group G2 consistsof five lenses L2 a to L2 e in order from the object side, and the thirdlens group G3 consists of one lens L3 a. However, in the imaging lens ofthe present disclosure, the number of lenses composing each lens groupmay be different from that in the example shown in FIG. 1.

The imaging lens of the present disclosure is configured such that thedistance between the first lens group G1 and the second lens group G2changes during focusing from an object at infinity to an object at ashort distance and the mutual distance between all the lenses in thefirst lens group and the mutual distance between all the lenses in thesecond lens group are constant. The phrase “during focusing, the mutualdistance is constant” described herein means that the mutual distanceremains unchanged during focusing. By changing the distance between thelens groups during focusing, it is possible to suppress fluctuation infield curvature during focusing, as compared with the configuration inwhich focusing is performed by integrally moving the entire imaginglens. It should be noted that the term “integrally moving” describedherein means moving in the same amount and in the same direction at thesame time.

In the imaging lens of FIG. 1, as an example, during focusing from theobject at infinity to the closest object, the first lens group G1 andthe third lens group G3 remain stationary with respect to the imageplane Sim, and the second lens group G2 moves to the object side alongthe optical axis Z. That is, in the imaging lens of FIG. 1, the lensgroup that moves during focusing (hereinafter referred to as thefocusing lens group) consists of the second lens group G2. Thehorizontal left arrow under the second lens group G2 in FIG. 1 meansthat the second lens group G2 moves to the object side during focusingfrom the object at infinity to the closest object.

This imaging lens is configured such that the combined refractive powerof all the lenses closer to the object side than the aperture stop St ispositive. Further, this imaging lens is configured to include at leastone LA positive lens LA and at least one LB positive lens LB closer tothe object side than the aperture stop St. The LA positive lens LA isdisposed closer to the object side than the aperture stop St, and is apositive lens that satisfies Conditional Expressions (1) and (2), wherethe refractive index of the LA positive lens LA at the d line is NdA andthe Abbe number of the LA positive lens LA based on the d line is νdA.

1.86<NdA<2.2  (1)

10<νdA<35  (2)

The LB positive lens LB is disposed closer to the object side than theaperture stop St, and is a positive lens of which the Abbe number basedon the d line is largest among Abbe numbers of all positive lensescloser to the object side than the aperture stop St based on the d lineand which satisfies Conditional Expression (3). Here, the Abbe number ofthe LB positive lens LB based on the d line is νdB.

57<νdB<105  (3)

In the example of FIG. 1, the lens L1 c corresponds to the LA positivelens LA and the lens L1 b corresponds to the LB positive lens LB.

By not allowing the result of Conditional Expression (1) to be equal toor less than the lower limit, the absolute value of the radius ofcurvature of the lens is prevented from becoming excessively small.Therefore, occurrence of spherical aberration can be suppressed. By notallowing the result of Conditional Expression (1) to be equal to orgreater than the upper limit, the specific gravity of the lens isprevented from becoming excessively large. Thus, there is an advantagein achieving weight reduction.

By not allowing the result of Conditional Expression (2) to be equal toor less than the lower limit, there is an advantage in satisfactorilycorrecting first-order chromatic aberration. By not allowing the resultof Conditional Expression (2) to be equal to or greater than the upperlimit, there is an advantage in satisfactorily correcting second-orderchromatic aberration. By satisfying Conditional Expression (2), there isan advantage in satisfactorily correcting the first-order chromaticaberration and the second-order chromatic aberration.

By not allowing the result of Conditional Expression (3) to be equal toor less than the lower limit, there is an advantage in satisfactorilycorrecting chromatic aberration, particularly longitudinal chromaticaberration. By not allowing the result of Conditional Expression (3) tobe equal to or greater than the upper limit, it is possible to preventthe refractive index of the LB positive lens LB from becomingexcessively low. In a case where a positive lens is composed of amaterial having a low refractive index, spherical aberration and comaaberration are likely to occur. However, by not allowing the result ofConditional Expression (3) to be equal to or greater than the upperlimit, occurrence of spherical aberration and coma aberration can besuppressed.

In the imaging lens of the present disclosure, a high-refractive-indexand high-dispersion LA positive lens LA that satisfies ConditionalExpressions (1) and (2) is disposed closer to the object side than theaperture stop St, and a low-dispersion LB positive lens LB thatsatisfies Conditional Expression (3) is also disposed. The plurality oflenses disposed closer to the object side than the aperture stop St havepositive refractive power as a whole, and the LA positive lens LAcomposed of a material satisfying Conditional Expressions (1) and (2) isdisposed. Thereby, the correction effect of the second-order chromaticaberration can be obtained. By controlling the amount of chromaticaberration caused by the LA positive lens LA and the LB positive lensLB, the first-order chromatic aberration and the second-order chromaticaberration can be balanced. Further, by disposing the positive lenscomposed of the high-refractive-index material that satisfiesConditional Expression (1), it is possible to prevent the absolute valueof the radius of curvature of each positive lens from becomingexcessively small. This facilitates a balanced correction of chromaticaberration and monochromatic aberration such as spherical aberration andcoma aberration.

In order to obtain more favorable characteristics, it is preferable thatthe LA positive lens LA satisfies at least one of Conditional Expression(1-1), (1-2), (2-1), (2-2), or (2-3).

1.88<NdA<2.15  (1-1)

1.91<NdA<2.15  (1-2)

13.5<νdA<31  (2-1)

14<νdA<28  (2-2)

14.5<νdA<22  (2-3)

In order to obtain more favorable characteristics, the LB positive lensLB preferably satisfies Conditional Expression (3-1), and morepreferably satisfies Conditional Expression (3-2).

62<νdB<92  (3-1)

66<νdB<88  (3-2)

Further, assuming that the Abbe number of the LA positive lens LA basedon the d line is νdA and the partial dispersion ratio of the LA positivelens LA between the g line and the F line is θgFA, it is preferable tosatisfy Conditional Expression (17). By not allowing the result ofConditional Expression (17) to be equal to or less than the lower limit,it is possible to prevent second-order chromatic aberration from beinginsufficiently corrected. By not allowing the result of ConditionalExpression (17) to be equal to or greater than the upper limit, it ispossible to prevent second-order chromatic aberration from beingexcessively corrected. In order to obtain more favorablecharacteristics, it is more preferable to satisfy Conditional Expression(17-1).

0.01<θgFA+0.00162×νdA−0.64159<0.06  (17)

0.015<θgFA+0.00162×νdA−0.64159<0.055  (17-1)

In Conditional Expression (17), θgFA+0.00162×νdA−0.64159 is ΔθgFArepresented by the following expression.

ΔθgFA=θgFA−(−0.00162×νdA+0.64159) ΔθgFA is a value indicating theabnormal dispersion of the material used for the LA positive lens LA,and the larger this value, the higher the abnormal dispersion. Theabnormal dispersion can be considered in terms of using an orthogonalcoordinate system in which the horizontal axis represents the Abbenumber νd based on the d line and the vertical axis represents thepartial dispersion ratio θgF between the g line and the F line. In thisorthogonal coordinate system, a straight line passing through two pointsof (νd, θgF)=(60.49, 0.5436) and (νd, θgF)=(36.26, 0.5828) is set as areference line. The deviation from this reference line indicates thedegree of abnormal dispersion. ΔθgFA indicates the deviation of thepartial dispersion ratio from this reference line. The above definitionof deviation is based on the definition of abnormal dispersion of OharaInc.

Likewise, assuming that the partial dispersion ratio of the LB positivelens LB between the g line and the F line is θgFB, it is preferable tosatisfy Conditional Expression (18). θgFB+0.00162×νdA−0.64159 inConditional Expression (18) is a value indicating the abnormaldispersion of the material used for the LB positive lens LB, and thelarger this value, the higher the abnormal dispersion. By not allowingthe result of Conditional Expression (18) to be equal to or less thanthe lower limit, it becomes easy to satisfactorily correct chromaticaberration, particularly longitudinal chromatic aberration. By notallowing the result of Conditional Expression (18) to be equal to orgreater than the upper limit, a material other than the low refractiveindex material can be selected. Therefore, the absolute value of theradius of curvature of the lens can be prevented from becomingexcessively small. Thereby, it becomes easy to correct sphericalaberration and coma aberration. By satisfying conditional expression(18), it becomes easy to correct chromatic aberration, sphericalaberration, and coma aberration in a balanced manner. In order to obtainmore favorable characteristics, it is more preferable to satisfyConditional Expression (18-1).

0.01<θgFB+0.00162×νdB−0.64159<0.05  (18)

0.012<θgFB+0.00162×νdB−0.64159<0.035  (18-1)

Another preferable configuration and another possible configuration ofthe imaging lens of the present disclosure will be described below. Itis preferable that during focusing, the first lens group G1 remainsstationary with respect to the image plane Sim, and the first lens groupG1 includes at least one LA positive lens LA. The reason for this is asfollows. In a case where the LA positive lens LA composed of a materialhaving a high refractive index and a high dispersion is disposed in thefocusing lens group, fluctuations in chromatic aberration and sphericalaberration are likely to be large during focusing. Thus, it is desirablethat the LA positive lens LA is disposed in the first lens group thatdoes not move. Alternatively, in a case where the LA positive lens LA isdisposed in the focusing lens group, it is necessary for a negative lensto be further disposed in the focusing lens group in order to cancel theaberration occurring in the LA positive lens LA. This leads to anincrease in size of the lens group. From the above circumstances, it ismore preferable that the first lens group G1 remains stationary withrespect to the image plane Sim during focusing, and the first lens groupG1 includes all the LA positive lenses LA.

It is preferable that the imaging lens includes at least one LC positivelens LC closer to the object side than the aperture stop St. The LCpositive lens LC is a positive lens that is disposed closer to theobject side than the aperture stop St and has the largest or secondlargest Abbe number based on the d line among all the positive lensescloser to the object side than the aperture stop St, and is a positivelens that satisfies Conditional Expression (6). Here, the Abbe number ofthe LC positive lens LC based on the d line is νdC.

57<νdC<102  (6)

FIG. 1 shows an example in which the lens L1 d corresponds to the LCpositive lens LC.

By not allowing the result of Conditional Expression (6) to be equal toor less than the lower limit, it is possible to satisfactorily correctchromatic aberration, particularly longitudinal chromatic aberration. Bynot allowing the result of Conditional Expression (6) to be equal to orgreater than the upper limit, the refractive index of the LC positivelens LC is prevented from becoming excessively low. Therefore,occurrence of spherical aberration and coma aberration can besuppressed. The imaging lens has, at a position closer to the objectside than the aperture stop St, an LB positive lens LB composed of a lowdispersion material that satisfies Conditional Expression (3), and hasthe LC positive lens LC composed of a low dispersion material thatsatisfies Conditional Expression (6). Thereby, it is possible tosatisfactorily correct chromatic aberration and spherical aberration. Inthe configuration having the LB positive lens LB and the LC positivelens LC, the refractive power of the LB positive lens LB can be weakenedas compared with the configuration in which the positive lens composedof the low dispersion material is only the LB positive lens LB. As aresult, the absolute value of the radius of curvature of the LB positivelens LB is prevented from becoming excessively small. Therefore,occurrence of spherical aberration can be suppressed. Further, it ispossible to make the refractive index of the LC positive lens LC higherthan that of the LB positive lens LB due to the characteristics of therefractive index and Abbe number of the optical material. Therefore, ina case where the imaging lens has two positive lenses formed of alow-dispersion material closer to the object side than the aperture stopSt, as compared with the configuration in which both of these two lensesare LB positive lenses LB, in the configuration in which these twolenses are one LB positive lens LB and one LC positive lens LC, theabsolute value of the radius of curvature of these two positive lensescan be increased. Thus, there is an advantage in suppressing occurrenceof spherical aberration.

In order to obtain more favorable characteristics, the LC positive lensLC preferably satisfies Conditional Expression (6-1), and morepreferably Conditional Expression (6-2).

62<νdC<88  (6-1)

66<νdC<80  (6-2)

Assuming that the minimum value of the refractive indexes of allpositive lenses closer to the object side than the aperture stop St atthe d line is Ndfm, it is preferable to satisfy Conditional Expression(7). By not allowing the result of Conditional Expression (7) to beequal to or less than the lower limit, the absolute value of the radiusof curvature of the lens is prevented from becoming excessively small,and occurrence of spherical aberration can be suppressed. Further, thepositive lens disposed in the first lens group G1 having a large lensdiameter is prevented from becoming excessively thick. Thus, there is anadvantage in reducing the size of the lens system. By not allowing theresult of Conditional Expression (7) to be equal to or greater than theupper limit, a low dispersion material can be selected. Thus, there isan advantage in correcting chromatic aberration. In order to obtain morefavorable characteristics, it is more preferable to satisfy ConditionalExpression (7-1).

1.46<Ndfm<1.72  (7)

1.52<Ndfm<1.68  (7-1)

It is preferable that the imaging lens includes at least two positivelenses closer to the image side than the aperture stop St. Assuming thatthe average value of the refractive indexes of all the positive lensescloser to the image side than the aperture stop St at the d line isNdpr, it is preferable to satisfy Conditional Expression (8). Bydisposing two or more positive lenses closer to the image side than theaperture stop St, astigmatism and field curvature can be satisfactorilycorrected. By not allowing the result of Conditional Expression (8) tobe equal to or less than the lower limit, the absolute value of theradius of curvature of the lens is prevented from becoming excessivelysmall. As a result, it becomes easy to satisfactorily correctastigmatism and field curvature. By not allowing the result ofConditional Expression (8) to be equal to or greater than the upperlimit, materials other than high-dispersion materials can be selected.Thus, there is an advantage in correcting chromatic aberration. In orderto obtain more favorable characteristics, it is more preferable tosatisfy Conditional Expression (8-1), and it is yet more preferable tosatisfy Conditional Expression (8-2).

1.77<Ndpr<2.15  (8)

1.81<Ndpr<2.1  (8-1)

1.87<Ndpr<2.05  (8-2)

It is preferable that the first lens group G1 includes at least twopositive lenses and at least two negative lenses. In such a case,spherical aberration, coma aberration, and longitudinal chromaticaberration can be satisfactorily corrected. As a result, it becomes easyto suppress fluctuation in aberration caused by change in distancebetween the first lens group G1 and the second lens group G2 duringfocusing.

It is preferable that three positive lenses are successively arranged inthe first lens group. In such a case, the height of the on-axis marginalray can be gently lowered by the three positive lenses successivelyarranged. Therefore, occurrence of spherical aberration can besuppressed. In order to more satisfactorily suppress occurrence ofspherical aberration, it is preferable that four positive lenses aresuccessively arranged in the first lens group.

It is preferable that the first lens group G1 includes at least twonegative lenses. Assuming that an average value of Abbe numbers of twonegative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup G1, it is preferable to satisfy Conditional Expression (4). TheAbbe numbers of “the two negative lenses selected from negative lenseshaving smaller Abbe numbers” may be equal. Specifically, in a case wherethere are two or more negative lenses having the minimum Abbe number ofall the negative lenses in the first lens group, the minimum value isνdn1. In a case where there is only one negative lens having the minimumAbbe number of all the negative lenses in the first lens group, anaverage value of the minimum value and a second smallest value of theAbbe numbers of all the negative lenses in the first lens group is νdn1.In order to avoid redundant description, in the above description, the“Abbe number based on the d line” is simply referred to as “Abbenumber”. By not allowing the result of Conditional Expression (4) to beequal to or less than the lower limit, there is an advantage insatisfactorily correcting second-order chromatic aberration. By notallowing the result of Conditional Expression (4) to be equal to orgreater than the upper limit, there is an advantage in satisfactorilycorrecting first-order chromatic aberration. By satisfying ConditionalExpression (4), there is an advantage in correcting first-orderchromatic aberration and second-order chromatic aberration in a balancedmanner. In order to obtain more favorable characteristics, it is morepreferable to satisfy Conditional Expression (4-1).

15<νdn1<28  (4)

16<νdn1<25  (4-1)

It is preferable that the first lens group G1 includes at least twonegative lenses. Assuming that an average value of Abbe numbers of twonegative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup G1, and an average value of partial dispersion ratios of twonegative lenses between a g line and an F line is θgFn1 where the twonegative lenses are selected from the negative lenses having smallerAbbe numbers based on the d line among the negative lenses included inthe first lens group G1, it is preferable to satisfy ConditionalExpression (19). Similarly to Conditional Expression (4), in ConditionalExpression (19), the Abbe numbers of “the two negative lenses selectedfrom negative lenses having smaller Abbe numbers” may be equal.Similarly to θgFA+0.00162×νdA−0.64159 in Conditional Expression (17),θgFn1+0.00162×νdn1−0.64159 in Conditional Expression (19) is a valueindicating the average value of the abnormal dispersion of two negativelenses selected from negative lenses having smaller Abbe numbers amongthe negative lenses arranged in the first lens group G1, and the largerthis value, the higher the abnormal dispersion. By not allowing theresult of Conditional Expression (19) to be equal to or less than thelower limit, it becomes easy to satisfactorily correct first-orderchromatic aberration. By not allowing the result of ConditionalExpression (19) to be equal to or greater than the upper limit, itbecomes easy to satisfactorily correct second-order chromaticaberration. By satisfying Conditional Expression (19), it becomes easyto correct first-order chromatic aberration and second-order chromaticaberration in a balanced manner. In order to obtain more favorablecharacteristics, it is more preferable to satisfy Conditional Expression(19-1).

0.01<θgFn1+0.00162×νdn1−0.64159<0.05  (19)

0.016<θgFn1+0.00162×νdn1−0.64159<0.042  (19-1)

It is preferable that the first lens group G1 includes at least threenegative lenses. In such a case, it becomes easy to satisfactorilycorrect chromatic aberration, and there is also an advantage incorrecting field curvature.

Assuming that a focal length of the first lens group G1 is f1 and afocal length of the imaging lens in a state where the object at infinityis in focus is f, it is preferable to satisfy Conditional Expression(10). By not allowing the result of Conditional Expression (10) to beequal to or less than the lower limit, the refractive power of the firstlens group G1 is prevented from becoming excessively strong. Thus, thereis an advantage in satisfactorily correcting various aberrations,particularly spherical aberration. By not allowing the result ofConditional Expression (10) to be equal to or greater than the upperlimit, the refractive power of the first lens group G1 is prevented frombecoming excessively weak. Thus, there is an advantage in shortening thetotal lens length. In order to obtain more favorable characteristics, itis more preferable to satisfy Conditional Expression (10-1), it is yetmore preferable to satisfy Conditional Expression (10-2), and it is mostpreferable to satisfy Conditional Expression (10-3).

0.5<f1/f<3.5  (10)

0.7<f1/f<3.3  (10-1)

1.4<f1/f<3.2  (10-2)

1.8<f1/f<2.9  (10-3)

The first lens group G1 may be configured to include, successively inorder from the position closest to the object side, a first unit Gs1that has a negative refractive power and a second unit Gs2 that isseparated from the first unit Gs1 by the maximum air distance on theoptical axis in the first lens group and has a positive refractivepower. The first unit Gs1 is a unit including at least one lens, and thesecond unit Gs2 is a unit consisting of one single lens or one cementedlens. In such a case, the first unit Gs1 and the second unit Gs2 can bemade to have the same configuration as a wide conversion lens. As aresult, it becomes easy to suppress sagittal coma aberration whilewidening the angle of view. In the example of FIG. 1, the first unit Gs1consists of the lens L1 a, and the second unit Gs2 consists of the lensL1 b.

In the configuration in which the first lens group G1 has the first unitGs1 and the second unit Gs2, assuming that the focal length of theimaging lens in the state where the object at infinity is in focus is f,and the combined focal length of all the lenses closer to the image sidethan the second unit Gs2 of the imaging lenses in the state where theobject at infinity is in focus is fm, it is preferable to satisfyConditional Expression (16). By not allowing the result of ConditionalExpression (16) to be equal to or less than the lower limit, there is anadvantage in reducing the coma aberration occurring in the first unitGs1 and the second unit Gs2. By not allowing the result of ConditionalExpression (16) to be equal to or greater than the upper limit, there isan advantage in reducing aberration, particularly coma aberration,occurring in the lens closer to the image side than the second unit Gs2.In order to obtain more favorable characteristics, it is more preferableto satisfy Conditional Expression (16-1).

0.7<f/fm<0.98  (16)

0.75<f/fm<0.95  (16-1)

In a case where the first lens group G1 has the above-mentioned firstunit Gs1 and second unit Gs2, it is preferable that the first unit Gs1consists of one negative lens and the second unit Gs2 consists of onepositive lens. In such a case, the number of lenses in the first unitGs1 and the second unit Gs2 having large lens diameters is small. Thus,there is an advantage in reducing the size and the weight of the imaginglens.

In the lens component closest to the object side and the lens componentwhich is second from the object side of the whole system, one has anegative refractive power and the other has a positive refractive power.In the state where the object at infinity is in focus, it is preferablethat the on-axis ray 2 emitted from the lens surface closest to theimage side in the one lens component having a negative refractive powerto the image side is divergent light. It should be noted that one lenscomponent means one single lens or one cemented lens. In the example ofFIG. 1, the lens L1 a that is the lens component closest to the objectside in the whole system has a negative refractive power, and the lensL1 b that is the lens component which is second from the object side ofthe whole system has a positive refractive power. As shown in FIG. 1,the on-axis ray 2 emitted from the lens L1 a to the image side betweenthe lens L1 a and the lens L1 b has a ray diameter that increases towardthe image side and is divergent light.

As described above, by disposing the lens component having a negativerefractive power at a position closer to the object, it is possible todecrease the angle of the principal ray with the maximum angle of view,which is emitted from the lens component having a negative refractivepower to the image side, with respect to the optical axis Z. Thus, itbecomes easy to suppress sagittal coma aberration. Further, by disposingthe lens component having a negative refractive power in the first lensgroup, it is possible to prevent a positive refractive power of thefirst lens group G1 from becoming excessively strong, and to suppressoccurrence of spherical aberration and field curvature. However, in acase where negative refractive powers are successively arranged suchthat both the lens component closest to the object side and the lenscomponent which is second from the object side have a negativerefractive power, the whole lens system becomes large. Therefore, it ispreferable that one of the two lens components has a negative refractivepower and the other has a positive refractive power. Further, by makingthe on-axis ray 2 emitted from the one lens component having a negativerefractive power as divergent light, it is possible to adopt aconfiguration in which the ray is once spread and then converged againin the first lens group G1 having a positive refractive power. Thus,there is an advantage in suppressing sagittal coma aberration.

It is preferable that at least one of the lens closest to the objectside or the lens which is second from the object side of the wholesystem is a negative lens of which the object side lens surface isconcave. By disposing the negative lens at a position closer to theobject in such a manner, it is possible to reduce the angle of theprincipal ray with the maximum angle of view, which is emitted from thenegative lens to the image side, with respect to the optical axis Z. Asa result, it becomes easy to suppress sagittal coma aberration. Further,by making the object side lens surface of the negative lens concave,there is an advantage in correcting spherical aberration.

It is preferable that the object side lens surface of the lens closestto the object side in the whole system is concave. In such a case, thereis an advantage in correcting spherical aberration.

It is preferable that the lens closest to the object side in the wholesystem is a negative lens. In such a case, it is possible to reduce theangle of the principal ray with the maximum angle of view, which isemitted from the lens closest to the object side to the image side, withrespect to the optical axis Z. Therefore, it becomes easy to suppresssagittal coma aberration.

The imaging lens may be configured to include a single lens having anegative refractive power, a single lens having a positive refractivepower, and a single lens having a positive refractive power,successively in order from the closest to the object side in the wholesystem. By making the lens closest to the object side a negative lens,it becomes easy to suppress sagittal coma aberration as described above.Moreover, since the positive lens that is disposed successively to thelens closest to the object side is able to gently lower the height ofthe on-axis marginal ray, it is possible to suppress occurrence ofspherical aberration. Further, by using only one negative lens among thethree lenses of the first lens to the third lens counted from the lensclosest to the object side, it is possible to suppress an increase insize of the lens system.

The second lens group G2 may be configured as a lens group having apositive refractive power. In such a case, the height of the on-axismarginal ray should be gently lowered until the light from the object isincident into the first lens group G1 having a positive refractive powerand is emitted from the second lens group G2. Therefore, occurrence ofspherical aberration can be suppressed even in a case where the F numberis reduced.

Assuming that a focal length of the first lens group G1 is f1, and afocal length of the second lens group G2 is f2, it is preferable tosatisfy Conditional Expression (13). By not allowing the result ofConditional Expression (13) to be equal to or less than the lower limit,it is possible to prevent the refractive power of the first lens groupG1 from becoming excessively strong. By not allowing the result ofConditional Expression (13) to be equal to or greater than the upperlimit, it is possible to prevent the refractive power of the second lensgroup G2 from becoming excessively strong. By satisfying ConditionalExpression (13), it becomes easy to suppress various aberrationsoccurring in each of the first lens group G1 and the second lens groupG2. In order to obtain more favorable characteristics, it is morepreferable to satisfy Conditional Expression (13-1), it is yet morepreferable to satisfy Conditional Expression (13-2), and it is mostpreferable to satisfy Conditional Expression (13-3).

1<f1/f2<5  (13)

1.2<f1/f2<4.4  (13-1)

2.3<f1/f2<4.2  (13-2)

2.5<f1/f2<4  (13-3)

It is preferable that the second lens group G2 includes at least twopositive lenses and at least two negative lenses. In such a case,various aberrations, particularly, field curvature can be satisfactorilycorrected. As a result, it becomes easy to suppress fluctuation inaberration caused by change in distance between the first lens group G1and the second lens group G2 during focusing.

It is preferable that the second lens group G2 includes at least threepositive lenses and at least two negative lenses. In such a case,various aberrations can be satisfactorily corrected. As a result, itbecomes easy to suppress fluctuation in aberration during focusing.

Regarding the behavior of each lens group during focusing, it ispreferable that the first lens group G1 remains stationary with respectto the image plane Sim and the second lens group G2 moves duringfocusing. In a lens system having a large aperture ratio, the lensclosest to the object side tends to have a large diameter, and thustends to have a heavy weight. Therefore, in a case where the first lensgroup G1 is configured to be moved during focusing, a plurality ofinconveniences will be described below. First, during focusing, a heavylens has to be moved, which makes an increase in autofocus speeddifficult. Further, a large motor having a high torque is required tomove the lens having a large weight. Therefore, the entire lens devicebecomes large. Furthermore, since the total lens length changes with themovement of the lens closest to the object side having a large diameter,the barycentric position of the imaging lens changes during imaging. Forthe above reasons, it is preferable to use the inner focus method or therear focus method. Further, the configuration in which the first lensgroup G1 does not move during focusing has an advantage that thefirmness of the lens device can be easily ensured.

It is preferable that the aperture stop St is disposed between the lensgroups, or it is preferable that the aperture stop St is disposed in thelens group that remains stationary with respect to the image plane Simduring focusing. That is, it is preferable that the aperture stop St isnot included in the focusing lens group. Since the focusing lens groupdoes not include the aperture stop unit, it is possible to reduce theweight of the focusing lens group and achieve an increase in autofocusspeed. Further, in a case where the focusing lens group can be reducedin weight, a large high torque motor becomes unnecessary. Thus, there isan advantage in achieving reduction in size and weight of the whole lenssystem.

From the above circumstances, in a case where importance is attached toreduction in size and weight and the like, it is preferable that theaperture stop St is disposed between the first lens group G1 and thesecond lens group G2, and the first lens group G1 and the aperture stopSt remain stationary with respect to the image plane Sim and the secondlens group G2 moves during focusing.

It is preferable that only one lens group moves during focusing. Byusing only one lens group that moves during focusing, the structure canbe simplified, and reduction in size and weight of the lens device canbe achieved. In a lens system having a large aperture ratio, the focaldepth is extremely low, and the performance change due to tilting and/oraxial misalignment of the lens is likely to be large. In particular, inthe focusing lens group which is the movable lens group, it is desirablethat the number of the movable lens groups is small since structurallyit is difficult to completely eliminate the tilting of the lens and theaxial misalignment.

As described above, it is preferable that the first lens group G1remains stationary with respect to the image plane Sim during focusing,and it is preferable that only one lens group moves during focusing.Therefore, it is preferable that the only lens group that moves duringfocusing is the second lens group G2.

In a case where the second lens group G2 moves during focusing, it ispreferable that the number of lenses included in the second lens groupG2 is 7 or less. By reducing the number of lenses in the second lensgroup G2, which is the focusing lens group, the weight of the focusinglens group can be reduced. Thus, there is an advantage in increasing theautofocus speed. Further, in a case where the focusing lens group can bereduced in weight, a large high torque motor becomes unnecessary. Thus,there is an advantage in achieving reduction in size and weight of thewhole lens system. Therefore, in the configuration in which the secondlens group G2 moves during focusing, the number of lenses included inthe second lens group G2 is more preferably 6 or less, and yet morepreferably 5 or less.

In the configuration in which the second lens group G2 moves duringfocusing, the second lens group G2 includes at least one positive lens.Assuming that the average value of the refractive indexes of all thepositive lenses in the second lens group at the d line is Nd2p, it ispreferable to satisfy Conditional Expression (9). By not allowing theresult of Conditional Expression (9) to be equal to or less than thelower limit, it becomes easy to satisfactorily correct astigmatism andfield curvature. By not allowing the result of Conditional Expression(9) to be equal to or greater than the upper limit, the specific gravityof the lens material is prevented from becoming excessively large.Therefore, the weight of the focusing lens group can be prevented frombecoming heavy. Further, since it is possible to select a material otherthan the high-dispersion material, it is possible to suppressfluctuation in chromatic aberration in a case where the focusing lensmoves. In order to obtain more favorable characteristics, it is morepreferable to satisfy Conditional Expression (9-1), it is yet morepreferable to satisfy Conditional Expression (9-2), and it is mostpreferable to satisfy Conditional Expression (9-3).

1.7<Nd2p<2.2  (9)

1.77<Nd2p<2.15  (9-1)

1.81<Nd2p<2.1  (9-2)

1.87<Nd2p<2.05  (9-3)

In a case where the second lens group G2 moves during focusing, it ispreferable that the second lens group G2 includes at least two cementedlenses. In this case, it is possible to suppress fluctuation inchromatic aberration during focusing.

In the configuration in which the second lens group G2 moves duringfocusing, assuming that a focal length of the second lens group G2 isf2, and a focal length of the imaging lens in a state where the objectat infinity is in focus is f, it is preferable to satisfy ConditionalExpression (12). By not allowing the result of Conditional Expression(12) to be equal to or less than the lower limit, the refractive powerof the second lens group G2 is prevented from becoming excessivelystrong. Therefore, it becomes easy to suppress occurrence of variousaberrations occurring in the second lens group G2. By not allowing theresult of Conditional Expression (12) to be equal to or greater than theupper limit, the amount of movement of the second lens group G2 duringfocusing can be reduced. Thus, there is an advantage in reducing thesize of the lens system. In order to obtain more favorablecharacteristics, it is more preferable to satisfy Conditional Expression(12-1), it is yet more preferable to satisfy Conditional Expression(12-2), and it is most preferable to satisfy Conditional Expression(12-3).

0.3<|f2|/f<2.2  (12)

0.4<|f2|/f<1.9  (12-1)

0.45<|f2|/f<1.2  (12-2)

0.5<|f2|/f<1  (12-3)

In the configuration in which the second lens group G2 moves duringfocusing, assuming that a lateral magnification of the second lens groupG2 in the state where an object at infinity is in focus is β2, and acombined lateral magnification of all lenses closer to the image sidethan the second lens group G2 in a state where the object at infinity isin focus is βr in a case where a lens is disposed closer to the imageside than the second lens group G2, and βr is set to 1 in a case whereno lens is disposed closer to the image side than the second lens groupG2, it is preferable to satisfy Conditional Expression (14). InConditional Expression (14), |(1−β2²)×βr²| represents the amount ofmovement of the image plane position with respect to the amount ofmovement of the second lens group G2 during focusing, and representsso-called focus sensitivity. By not allowing the result of ConditionalExpression (14) to be equal to or less than the lower limit, it ispossible to reduce the amount of movement of the second lens group G2during focusing. Thus, there is an advantage in reducing the size of thelens system. By not allowing the result of Conditional Expression (14)to be equal to or greater than the upper limit, it is possible tosuppress the strictness in accuracy of the stopping of the focusing lensgroup in the focusing operation. Further, by not allowing the result ofConditional Expression (14) to be equal to or greater than the upperlimit, it becomes unnecessary to increase the refractive power of thesecond lens group G2 for focus sensitivity. Therefore, it becomes easyto correct spherical aberration and coma aberration. In order to obtainmore favorable characteristics, it is more preferable to satisfyConditional Expression (14-1), and it is yet more preferable to satisfyConditional Expression (14-2).

0.3<|(1=β2²)×βr ²|<1.5  (14)

0.4<|(1−β2²)×βr ²|<1.4  (14-1)

0.6<|(1−β2²)×βr ²|<1  (14-2)

As shown in FIG. 1, it is preferable that the imaging lens of thepresent disclosure comprises, in order from the object side to the imageside, as lens groups, only three lens groups consisting of the firstlens group G1 that remains stationary with respect to the image planeSim during focusing, the second lens group G2 that moves duringfocusing, and a third lens group G3 that consists of two or less lensesand remains stationary with respect to the image plane Sim duringfocusing. Alternatively, as shown in examples described below, it ispreferable that the imaging lens of the present disclosure comprises, inorder from the object side to the image side, as lens groups, only twolens groups consisting of the first lens group G1 that remainsstationary with respect to the image plane Sim during focusing and thesecond lens group G2 that moves during focusing. The first lens group G1remains stationary with respect to the image plane Sim and the secondlens group G2 moves during focusing, and the operational effects are asdescribed above. In a case where the lens is not disposed closer to theimage side than the second lens group G2, it becomes easy to ensure thestroke of the second lens group G2, which is the focusing lens group,while suppressing an increase in total lens length. Alternatively, evenin a case where the lens is disposed closer to the image side than thesecond lens group G2, by reducing the number of the arranged lenses totwo or less, it becomes easy to ensure the stroke of the second lensgroup G2, which is the focusing lens group, while suppressing anincrease in total lens length. Thereby, it becomes easy to increase themaximum imaging magnification. In a case where a large number of lensesare arranged closer to the image side than the second lens group G2while maintaining the total lens length, the stroke of the second lensgroup G2 may be reduced and the maximum imaging magnification may bereduced. Alternatively, in a case where the refractive power of thesecond lens group G2 is increased in order to obtain the same maximumimaging magnification while maintaining the total lens length, variousaberrations, particularly spherical aberration and field curvature,which occur in the second lens group G2, increase.

The number of lenses included in the imaging lens is preferably 13 orless, and more preferably 12 or less. By configuring the imaging lenswith a small number of lenses, reduction in size and weight can beachieved.

The number of lenses disposed closer to the object side than theaperture stop St is preferably 8 or less, and more preferably 7 or less.A lens disposed closer to the object side than the aperture stop St islikely to have a large lens outer diameter and a heavy weight.Therefore, it is preferable to keep the number of lenses closer to theobject side than the aperture stop St small.

Assuming that a distance on an optical axis from a lens surface closestto the object side to the aperture stop St in a state where an object atinfinity is in focus is Tf, and a sum of a distance on an optical axisfrom a lens surface closest to the object side to a lens surface closestto the image side and a back focal length at an air-converted distancein the state where the object at infinity is in focus is TL, it ispreferable to satisfy Conditional Expression (15). The first lens groupG1 disposed closest to the object side has a positive refractive power.Thus, by not allowing the result of Conditional Expression (15) to beequal to or less than the lower limit, It is possible to further reducethe height of the ray in the lens disposed closer to the image side thanthe aperture stop St. Thereby, there is an advantage in suppressingoccurrence of various aberrations in the lens disposed closer to theimage side than the aperture stop St. Further, by not allowing theresult of Conditional Expression (15) to be less than or equal to thelower limit, it becomes easy to dispose as many lenses as necessary forcorrecting spherical aberration, longitudinal chromatic aberration, andthe like at the position closer to the object side than the aperturestop St. By not allowing the result of Conditional Expression (15) to beequal to or greater than the upper limit, it is possible to suppress anincrease in diameter of the lens disposed closer to the object side thanthe aperture stop St. Thus, it becomes easy to achieve reduction in sizeand weight of the whole lens system. In order to obtain more favorablecharacteristics, it is more preferable to satisfy Conditional Expression(15-1), and it is yet more preferable to satisfy Conditional Expression(15-2).

0.2<Tf/TL<0.65  (15)

0.4<Tf/TL<0.64  (15-1)

0.48<Tf/TL<0.61  (15-2)

Assuming that a sum of a distance on an optical axis from a lens surfaceclosest to the object side to a lens surface closest to the image sideand a back focal length at an air-converted distance in a state where anobject at infinity is in focus is TL, an F number of the imaging lens inthe state where the object at infinity is in focus is FNo, and a focallength of the imaging lens in the state where the object at infinity isin focus is f, it is preferable that Conditional Expression (5) issatisfied. By not allowing the result of Conditional Expression (5) tobe equal to or less than the lower limit, there is an advantage insatisfactorily correcting various aberrations. More specifically, itbecomes easy to arrange the optimum number of lenses to correct variousaberrations. Thus, there is an advantage in obtaining higher imagingperformance By not allowing the result of Conditional Expression (5) tobe equal to or greater than the upper limit, there is an advantage insuppressing an increase in size of the lens system. In order to obtainmore favorable characteristics, it is more preferable to satisfyConditional Expression (5-1), and it is yet more preferable to satisfyConditional Expression (5-2).

1.5<TL×FNo/f<5  (5)

1.8<TL×FNo/f<3.5  (5-1)

2<TL×FNo/f<3.2  (5-2)

Assuming that a maximum half angle of view of the imaging lens in astate where an object at infinity is in focus is ω max, and an F numberof the imaging lens in the state where the object at infinity is infocus is FNo, it is preferable to satisfy Conditional Expression (11).Considering Conditional Expression (11) on the assumption that a small Fnumber is maintained, the smaller the value of 1/{tan(ω max)×FNo} ofConditional Expression (11) is, the lens system becomes a wider-angletype optical system. As the value becomes lager, the lens system becomescloser to the telephoto type optical system. In a case where the resultof Conditional Expression (11) is equal to or less than the lower limitwhile a small F number is maintained, it becomes difficult to correctsagittal coma aberration. In order to correct sagittal coma aberration,the number of lenses of the first lens group G1 having a large outerdiameter increases. As a result, there is a problem in that the size ofthe lens system may increase. On the other hand, in a case where theresult of Conditional Expression (11) is equal to or greater than theupper limit while a small F number is maintained, the entrance pupildiameter becomes large and the diameter of the whole lens system becomeslarge. As a result, there is a problem in that the size of the lenssystem may increase. Alternatively, there is a problem in that it may benecessary to increase the total lens length in order to correctlongitudinal chromatic aberration that occurs as the lens system becomescloser to a telephoto type optical system. As described above, bysatisfying Conditional Expression (11), there is an advantage inachieving both a small F number and reduction in size of the lenssystem. In order to obtain more favorable characteristics, it is morepreferable to satisfy Conditional Expression (11-1), and it is yet morepreferable to satisfy Conditional Expression (11-2).

1.8<1/{tan(ω max)×FNo}<4.5  (11)

2.4<1/{tan(ω max)×FNo}<4.2  (11-1)

2.8<1/{tan(ω max)×FNo}<3.8  (11-2)

Next, a possible configuration example of the imaging lens of thepresent disclosure will be described. In each of the first to fifteenthconfiguration examples described below, only the second lens group G2 isconfigured to move along the optical axis Z during focusing. In thefollowing description of the configuration examples, “first”, “second”and the like attached to the cemented lenses are given for eachconfiguration example. Therefore, for example, even in the case of the“first cemented lens”, the configurations of the lenses included in thecemented lens may be different in a case where the configurationexamples are different.

The imaging lens of the first configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,a second lens group G2, and a third lens group G3. The first lens groupG1 consists of, in order from the object side, a biconcave lens, apositive lens convex toward the image side, two positive meniscus lenseseach of which is convex toward the object side, a first cemented lens,and a negative meniscus lens convex toward the object side. The firstcemented lens is configured such that a positive meniscus lens convextoward the object side and a negative meniscus lens convex toward theobject side are cemented in order from the object side. The second lensgroup G2 consists of, in order from the object side, a negative meniscuslens concave toward the object side, a second cemented lens, and a thirdcemented lens. The second cemented lens is formed by cementing abiconvex lens and a biconcave lens in order from the object side. Thethird cemented lens is formed by cementing a biconvex lens and anegative lens concave toward the object side in order from the objectside. The third lens group G3 consists of only biconvex lenses.

The imaging lens of the second configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,and a second lens group G2. The first lens group G1 and the second lensgroup G2 of the second configuration example are the same as the firstlens group G1 and the second lens group G2 of the first configurationexample, respectively.

The imaging lens of the third configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,and a second lens group G2. The first lens group G1 consists of, inorder from the object side, a biconcave lens, a positive meniscus lensconvex toward the object side, a biconvex lens, a positive meniscus lensconvex toward the object side, a first cemented lens, and a negativemeniscus lens convex toward the object side. The first cemented lens isconfigured such that a positive meniscus lens convex toward the objectside and a negative meniscus lens convex toward the object side arecemented in order from the object side. The second lens group G2consists of, in order from the object side, a second cemented lens, anegative meniscus lens concave toward the object side, and a thirdcemented lens. The second cemented lens is formed by cementing abiconcave lens and a biconvex lens in order from the object side. Thethird cemented lens is formed by cementing a biconvex lens and abiconcave lens in order from the object side.

The imaging lens of the fourth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,and a second lens group G2. The first lens group G1 consists of, inorder from the object side, a biconcave lens, a biconvex lens, threepositive lenses convex toward the object side, a first cemented lens,and a negative meniscus lens convex toward the object side. The firstcemented lens is formed by cementing a biconvex lens and a biconcavelens in order from the object side. The second lens group G2 consistsof, in order from the object side, a second cemented lens, a biconcavelens, and a third cemented lens. The second cemented lens is formed bycementing a biconcave lens and a biconvex lens in order from the objectside. The third cemented lens is formed by cementing a biconvex lens anda negative meniscus lens concave toward the object side in order fromthe object side.

The imaging lens of the fifth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,and a second lens group G2. The first lens group G1 consists of, inorder from the object side, a biconcave lens, a biconvex lens, threepositive meniscus lenses each of which is convex toward the object side,and two negative meniscus lenses convex toward the object side. Thesecond lens group G2 consists of, in order from the object side, anegative meniscus lens concave toward the object side, a first cementedlens, and a second cemented lens. The first cemented lens is formed bycementing a biconvex lens and a biconcave lens in order from the objectside. The third cemented lens is formed by cementing a biconvex lens anda negative meniscus lens concave toward the object side in order fromthe object side.

The imaging lens of the sixth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,a second lens group G2, and a third lens group G3. The first lens groupG1 consists of, in order from the object side, three positive meniscuslenses each of which is convex toward the object side, a first cementedlens, and a second cemented lens. The first cemented lens is formed bycementing a negative meniscus lens convex toward the object side and abiconvex lens in order from the object side. The second cemented lens isformed by cementing a biconcave lens and a positive meniscus lens convextoward the object side in order from the object side. The second lensgroup G2 consists of, in order from the object side, a third cementedlens and a fourth cemented lens. The third cemented lens is formed bycementing a biconcave lens and a biconvex lens in order from the objectside. The fourth cemented lens is formed by cementing a positivemeniscus lens concave toward the object side and a biconcave lens inorder from the object side. The third lens group G3 consists of, inorder from the object side, a biconvex lens, a fifth cemented lens, abiconvex lens, and a biconcave lens. The fifth cemented lens is formedby cementing a positive lens convex toward the image side and abiconcave lens in order from the object side.

The imaging lens of the seventh configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,a second lens group G2, and a third lens group G3. The first lens groupG1 consists of, in order from the object side, a biconcave lens, abiconvex lens, two positive meniscus lenses each of which is convextoward the object side, a first cemented lens, and a second cementedlens. The first cemented lens is formed by cementing a negative meniscuslens convex toward the object side and a biconvex lens in order from theobject side. The second cemented lens is formed by cementing a biconcavelens and a positive lens convex toward the object side in order from theobject side. The second lens group G2 and the third lens group G3 of theseventh configuration example are similar to the second lens group G2and the third lens group G3 of the sixth configuration example,respectively.

The imaging lens of the eighth configuration example consists of, inorder from the object side, a first lens group G1 and a second lensgroup G2. The first lens group G1 consists of, in order from the objectside, a biconcave lens, a first cemented lens, a biconvex lens, a secondcemented lens, a biconvex lens, and a positive meniscus lens convextoward the object side. The first cemented lens is formed by cementing abiconcave lens and a biconvex lens in order from the object side. Thesecond cemented lens is formed by cementing a biconvex lens and anegative meniscus lens concave toward the object side in order from theobject side. The second lens group G2 consists of, in order from theobject side, a positive meniscus lens convex toward the object side, athird cemented lens, an aperture stop St, a negative meniscus lensconcave toward the object side, and a fourth cemented lens. The thirdcemented lens is formed by cementing a biconvex lens and a biconcavelens in order from the object side. The fourth cemented lens is formedby cementing a biconvex lens, a biconcave lens, and a biconvex lens inorder from the object side.

The imaging lens of the ninth configuration example consists of, inorder from the object side, a first lens group G1 and a second lensgroup G2. The first lens group G1 consists of, in order from the objectside, a positive lens convex toward the image side, a biconcave lens, afirst cemented lens, a second cemented lens, a biconvex lens, and apositive meniscus lens convex toward the object side. The first cementedlens is formed by cementing a biconcave lens and a biconvex lens inorder from the object side. The second cemented lens is formed bycementing a biconvex lens and a negative meniscus lens concave towardthe object side in order from the object side. The second lens group G2consists of, in order from the object side, a positive meniscus lensconvex toward the object side, a third cemented lens, an aperture stopSt, a fourth cemented lens, and a biconvex lens. The third cemented lensis formed by cementing a biconvex lens and a biconcave lens in orderfrom the object side. The fourth cemented lens is configured such that anegative meniscus lens concave toward the object side and a positivemeniscus lens concave toward the object side are cemented in order fromthe object side.

The imaging lens of the tenth configuration example consists of, inorder from the object side, a first lens group G1 and a second lensgroup G2. The first lens group G1 of the tenth configuration example issimilar to the first lens group G1 of the ninth configuration example.The second lens group G2 of the tenth configuration example consists of,in order from the object side, a positive meniscus lens convex towardthe object side, a third cemented lens, an aperture stop St, a negativemeniscus lens concave toward the object side, a positive meniscus lensconcave toward the object side, and a fourth cemented lens. The thirdcemented lens is formed by cementing a biconvex lens and a biconcavelens in order from the object side. The fourth cemented lens is formedby cementing a biconvex lens and a biconcave lens in order from theobject side.

The imaging lens of the eleventh configuration example consists of, inorder from the object side, a first lens group G1, a second lens groupG2, and a third lens group G3. The first lens group G1 consists of, inorder from the object side, a positive meniscus lens convex toward theimage side, a biconcave lens, a biconvex lens, a first cemented lens,and a second cemented lens. The first cemented lens is formed bycementing a biconcave lens and a biconvex lens in order from the objectside. The second cemented lens is formed by cementing a biconvex lensand a negative meniscus lens concave toward the object side in orderfrom the object side. The second lens group G2 consists of, in orderfrom the object side, a positive meniscus lens convex toward the objectside, a third cemented lens, an aperture stop St, a fourth cementedlens, and a biconvex lens. The third cemented lens is formed bycementing a biconvex lens and a biconcave lens in order from the objectside. The fourth cemented lens is formed by cementing a biconcave lensand a biconvex lens in order from the object side. The third lens groupG3 consists of a cemented lens in which a positive meniscus lens concavetoward the object side and a negative meniscus lens concave toward theobject side are cemented in order from the object side.

The imaging lens of the twelfth configuration example consists of, inorder from the object side, a first lens group G1 and a second lensgroup G2. The first lens group G1 consists of, in order from the objectside, a biconcave lens, a first cemented lens, a biconvex lens, a secondcemented lens, a third cemented lens, and a biconvex lens. The firstcemented lens is formed by cementing a biconcave lens and a biconvexlens in order from the object side. The second cemented lens is formedby cementing a biconcave lens and a positive meniscus lens convex towardthe object side in order from the object side. The third cemented lensis formed by cementing a biconvex lens and a negative meniscus lensconcave toward the object side in order from the object side. The secondlens group G2 consists of, in order from the object side, a positivemeniscus lens convex toward the object side, a fourth cemented lens, anaperture stop St, a biconcave lens, and a fifth cemented lens. Thefourth cemented lens is formed by cementing a biconvex lens and abiconcave lens in order from the object side. The fifth cemented lens isformed by cementing a biconvex lens, a biconcave lens, and a biconvexlens in order from the object side.

The imaging lens of the thirteenth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,a second lens group G2, and a third lens group G3. The first lens groupG1 consists of, in order from the object side, a biconcave lens, a firstcemented lens, a biconvex lens, a second cemented lens, a third cementedlens, two positive meniscus lenses each of which is convex toward theobject side, a fourth cemented lens, and a negative meniscus lens convextoward the object side. The first cemented lens is formed by cementing abiconcave lens and a biconvex lens in order from the object side. Thesecond cemented lens is formed by cementing a positive meniscus lensconcave toward the object side and a biconcave lens in order from theobject side. The third cemented lens is formed by cementing a biconvexlens and a negative meniscus lens concave toward the object side inorder from the object side. The fourth cemented lens is formed bycementing a biconvex lens and a biconcave lens in order from the objectside. The second lens group G2 consists of, in order from the objectside, a negative meniscus lens concave toward the object side, and afifth cemented lens. The fifth cemented lens is formed by cementing abiconvex lens, a biconcave lens, and a biconvex lens in order from theobject side. The third lens group G3 consists of only a plano-concavelens concave toward the object side.

The imaging lens of the fourteenth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,and a second lens group G2. The first lens group G1 consists of, inorder from the object side, a biconcave lens, a first cemented lens, abiconvex lens, a biconcave lens, a second cemented lens, a biconvexlens, a positive meniscus lens convex toward the object side, a thirdcemented lens, and a negative meniscus lens convex toward the objectside. The first cemented lens is formed by cementing a biconcave lensand a biconvex lens in order from the object side. The second cementedlens is formed by cementing a biconvex lens and a negative meniscus lensconcave toward the object side in order from the object side. The thirdcemented lens is formed by cementing a biconvex lens and a biconcavelens in order from the object side. The second lens group G2 consistsof, in order from the object side, a biconcave lens, a fourth cementedlens, and a biconvex lens. The fourth cemented lens is formed bycementing a biconvex lens and a biconcave lens in order from the objectside.

The imaging lens of the fifteenth configuration example consists of, inorder from the object side, a first lens group G1, an aperture stop St,a second lens group G2, and a third lens group G3. The first lens groupG1 consists of, in order from the object side, a biconcave lens, a firstcemented lens, a biconvex lens, a second cemented lens, a third cementedlens, a biconvex lens, two positive meniscus lenses each of which isconvex toward the object side, a fourth cemented lens, and a negativemeniscus lens convex toward the object side. The first cemented lens isformed by cementing a biconcave lens and a biconvex lens in order fromthe object side. The second cemented lens is formed by cementing apositive meniscus lens concave toward the object side and a biconcavelens in order from the object side. The third cemented lens is formed bycementing a biconvex lens and a negative meniscus lens concave towardthe object side in order from the object side. The fourth cemented lensis formed by cementing a biconvex lens and a biconcave lens in orderfrom the object side. The second lens group G2 consists of, in orderfrom the object side, a negative meniscus lens concave toward the objectside, and a fifth cemented lens. The fifth cemented lens is formed bycementing, in order from the object side, a biconvex lens, a negativemeniscus lens concave toward the object side, and a positive meniscuslens concave toward the object side. The third lens group G3 consists ofa plano-convex lens convex toward the object side.

The above-mentioned preferred configurations and availableconfigurations may be optional combinations, and it is preferable toselectively adopt the configurations in accordance with requiredspecification. According to the technology of the present disclosure, itis possible to realize a suitable imaging lens which has a small Fnumber and in which aberration is satisfactorily corrected.

Next, numerical examples of the imaging lens of the present disclosurewill be described.

Example 1

FIG. 1 shows a cross-sectional configuration of an imaging lens ofExample 1, and an illustration method and a configuration thereof is asdescribed above. Therefore, repeated description is partially omittedherein. The imaging lens of Example 1 consists of, in order from theobject side, a first lens group G1 that has a positive refractive power,an aperture stop St, a second lens group G2 that has a positiverefractive power, and a third lens group G3 that has a positiverefractive power. During focusing from the object at infinity to theclosest object, the first lens group G1 and the third lens group G3remain stationary with respect to the image plane Sim, and the secondlens group G2 moves to the object side along the optical axis Z. Thefirst lens group G1 consists of seven lenses L1 a to L1 g in order fromthe object side. The second lens group G2 consists of five lenses L2 ato L2 e in order from the object side. The third lens group G3 consistsof one lens L3 a.

Regarding the imaging lens of Example 1, Table 1 shows basic lens data,Table 2 shows a specification, Table 3 shows variable surface distances,and Table 4 shows aspheric surface coefficients. In Table 1, the columnof Sn shows surface numbers. The surface closest to the object side isthe first surface, and the surface numbers increase one by one towardthe image side. The column of R shows radii of curvature of therespective surfaces. The column of D shows surface distances on theoptical axis between the respective surfaces and the surfaces adjacentto the image side. Further, the column of Nd shows a refractive index ofeach constituent element at the d line, the column of νd shows an Abbenumber of each constituent element based on the d line, and the columnof θgF shows a partial dispersion ratio of each constituent elementbetween the g line and the F line.

In Table 1, the sign of the radius of curvature of the surface convextoward the object side is positive and the sign of the radius ofcurvature of the surface convex toward the image side is negative. Table1 also shows the aperture stop St and the optical member PP, and in thecolumn of the surface number of the surface corresponding to theaperture stop St, the surface number and (St) are noted. A value at thebottom place of D in Table 1 indicates a distance between the imageplane Sim and the surface closest to the image side in the table. InTable 1, the variable surface distances, which are distances variableduring focusing, are referenced by the reference signs DD[ ], and arewritten into places of D, where object side surface numbers of distancesare noted in [ ].

Table 2 shows values of the focal length f, the F number FNo., and themaximum total angle of view 2ω max of the imaging lens. FNo. is the sameas FNo used in the above conditional expression. The unit of 2ω max isdegree. The values shown in Table 2 are values in the case of using thed line as a reference in a state where the object at infinity is infocus.

In Table 3, the column labelled “Infinity” shows values of the variablesurface distance in the state where the object at infinity is in focusand the column labelled “0.7 m” shows values of the variable surfacedistance in the state where an object at a distance of 0.7 m (meters)from the object to the image plane Sim is in focus.

In Table 1, the reference sign * is attached to surface numbers ofaspheric surfaces, and numerical values of the paraxial radius ofcurvature are written into the column of the radius of curvature of theaspheric surface. In Table 4, the row of Sn shows surface numbers of theaspheric surfaces, and the rows of KA and Am (m is an integer of 3 ormore, and is different for each surface) shows numerical values of theaspheric surface coefficients for each aspheric surface. The “E±n” (n:an integer) in numerical values of the aspheric surface coefficients ofTable 4 indicates “′10^(±n)”. KA and Am are the aspheric surfacecoefficients in the aspheric surface expression represented by thefollowing expression.

Zd=C×h ²/{1+(1−KA×C ² ×h ²)^(1/2) }+ΣΔm×h ^(m)

-   -   Here,    -   Zd is an aspheric surface depth (a length of a perpendicular        from a point on an aspheric surface at height h to a plane that        is perpendicular to the optical axis and contacts with the        vertex of the aspheric surface),    -   h is a height (a distance from the optical axis to the lens        surface),    -   C is an inverse of paraxial radius of curvature,    -   KA and Am are aspheric surface coefficients, and    -   Σ in the aspheric surface expression means the sum with respect        to m.

In data of each table, a degree is used as a unit of an angle, and mm(millimeter) is used as a unit of a length, but appropriate differentunits may be used since the optical system can be used even in a casewhere the system is enlarged or reduced in proportion. Further, each ofthe following tables shows numerical values rounded off to predetermineddecimal places.

TABLE 1 Example 1 Sn R D Nd νd θgF  1 −202.46222 2.400 1.61750 36.250.58409  2 84.17703 10.655  3 116.82988 10.000 1.45860 90.19 0.53516  4−99.70316 1.010  5 58.97589 6.168 2.00272 19.32 0.64514  6 157.481120.200  7 39.80574 10.250 1.59282 68.62 0.54414  8 93.85195 0.200  932.50135 7.910 1.53945 63.48 0.53990 10 113.27635 1.500 1.85896 22.730.62844 11 30.08960 2.350 12 48.57213 1.500 1.98613 16.48 0.66558 1323.70172 7.000   14(St) ∞ DD[14] *15  −16.62654 1.800 1.68948 31.020.59874 *16  −20.47694 0.200 17 46.52462 7.524 1.95375 32.32 0.59015 18−24.94567 1.110 1.78555 25.72 0.61045 19 32.92450 1.205 20 53.581238.896 1.95375 32.32 0.59015 21 −21.67977 1.210 1.63849 34.39 0.58799 22121.65386 DD[22] 23 350.00000 2.000 1.90602 23.33 0.62075 24 −350.0000012.401 25 ∞ 2.850 1.51680 64.20 0.53430 26 ∞ 1.000

TABLE 2 Example 1 f 51.529 FNo. 1.03 2ωmax 30.6

TABLE 3 Example 1 Infinity 0.7 m DD[14] 11.000 5.227 DD[22] 1.004 6.777

TABLE 4 Example 1 Sn 15 16 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 1.4134736E−05 1.5709981E−05 A52.6259559E−05 2.5965284E−05 A6 −3.3907589E−06  −4.2475360E−06  A7−2.4053109E−07  −1.2459177E−08  A8 1.0812258E−07 1.0406812E−07 A9−2.4866912E−09  −8.5930892E−09  A10 −1.7843185E−09  −1.0929846E−09  A111.2258615E−10 1.6907154E−10 A12 1.6697433E−11 4.3662373E−12 A13−1.8317390E−12  −1.5987613E−12  A14 −7.6120774E−14  1.5986683E−14 A151.4012767E−14 8.3615812E−15 A16 2.5265457E−17 −2.3879418E−16  A17−5.5017957E−17  −2.3215598E−17  A18 1.1014057E−18 9.2450531E−19 A198.7746514E−20 2.6760815E−20 A20 −2.9531051E−21  −1.2643529E−21 

FIGS. 2 and 3 each show aberration diagrams of the imaging lens ofExample 1. FIG. 2 shows spherical aberration diagrams, astigmatismdiagrams, distortion diagrams, and lateral chromatic aberration diagramsin order from the left. In FIG. 2, the upper part labeled “INFINITY”shows aberration diagrams in a state where the object at infinity is infocus, and the lower part labeled “0.7 m” shows aberration diagrams in astate where an object at the distance of 0.7 m (meter) from the objectto the image plane Sim is in focus. In the spherical aberration diagram,aberrations at the d line, the C line, the F line, and the g line areindicated by the solid line, the long dashed line, the short dashedline, and the chain line, respectively. In the astigmatism diagram,aberration in the sagittal direction at the d line is indicated by thesolid line, and aberration in the tangential direction at the d line isindicated by the short dashed line. In the distortion diagram,aberration at the d line is indicated by the solid line. In the lateralchromatic aberration diagram, aberrations at the C line, the F line, andthe g line are respectively indicated by the long dashed line, the shortdashed line, and the chain line. In the spherical aberration diagram,FNo. indicates an F number. In the other aberration diagrams, ωindicates a half angle of view. In FIG. 2, values of FNo. and ωcorresponding to the upper part in the vertical axis of each diagram areshown next to “=”.

FIG. 3 shows lateral aberration diagram in a state wherestate where theobject at infinity is in focus. The left column shows tangentialaberration and the right column shows sagittal aberration for each angleof view. In FIG. 3, ω means a half angle of view. In the lateralaberration diagram, aberrations at the d line, the C line, the F line,and the g line are indicated by the solid line, the long dashed line,the short dashed line, and the chain line, respectively.

Symbols, meanings, description methods, and illustration methods of therespective data pieces according to Example 1 are the same as those inthe following examples unless otherwise noted. Therefore, in thefollowing description, repeated description will be partially omitted.

Example 2

FIG. 4 shows a cross-sectional configuration of the imaging lens ofExample 2. The imaging lens of Example 2 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 2, Table 5 shows basic lens data,Table 6 shows specification, Table 7 shows variable surface distances,Table 8 shows aspheric surface coefficients, and FIGS. 5 and 6 showaberration diagrams. In FIG. 5, the upper part shows aberration diagramsin a state where the object at infinity is in focus, and the lower partshows aberration diagrams in a state where the object at the distance of0.75 m (meter) from the object to the image plane Sim is in focus. FIG.6 shows lateral aberration diagram in a state where the object atinfinity is in focus.

TABLE 5 Example 2 Sn R D Nd νd θgF  1 −147.83201 2.400 1.56607 42.610.57194  2 86.55844 13.196   3 −1112.59959 10.000  1.49700 81.61 0.53887 4 −74.96995 1.010  5 56.10284 7.350 1.92286 20.88 0.63900  6 168.762780.200  7 39.99940 10.364  1.49700 81.61 0.53887  8 153.92109 0.200  933.63361 9.003 1.58350 61.79 0.54178 10 143.73093 1.500 1.89286 20.360.63944 11 32.94000 2.350 12 58.54173 1.500 1.98613 16.48 0.66558 1326.84925 7.000   14(St) ∞ DD[14] *15  −16.34007 2.374 1.68948 31.020.59874 *16  −20.92321 0.200 17 46.16889 5.601 2.00100 29.13 0.59952 18−34.75772 1.110 1.82933 23.53 0.61772 19 36.00359 1.259 20 65.484637.692 2.00100 29.13 0.59952 21 −21.60337 1.210 1.72399 28.80 0.60142 22−221.70851 DD[22] 23 ∞ 2.850 1.51680 64.20 0.53430 24 ∞ 1.000

TABLE 6 Example 2 f 48.912 FNo. 1.03 2ωmax 32.2

TABLE 7 Example 2 Infinity 0.75 m DD[14] 11.000 6.974 DD[22] 15.39819.418

TABLE 8 Example 2 Sn 15 16 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 1.1642920E−05 1.4474213E−05 A52.1306014E−05 2.0258437E−05 A6 −3.3814546E−06  −4.0400080E−05  A7−1.9812243E−07  4.7913832E−08 A8 1.0663262E−07 9.6017868E−08 A9−1.5803952E−09  −8.4598138E−09  A10 −1.8092896E−09  −9.9449719E−10  A119.0694353E−11 1.5710711E−10 A12 1.8185970E−11 4.0001956E−12 A13−1.4218748E−12  −1.4517868E−12  A14 −9.8519189E−14  1.3061204E−14 A151.1294372E−14 7.4850181E−15 A16 1.8703189E−16 −2.0136740E−16  A17−4.5775183E−17  −2.0557864E−17  A18 5.1939904E−19 7.6973691E−19 A197.4994186E−20 2.3482464E−20 A20 −2.1146255E−21  −1.0301864E−21 

Example 3

FIG. 7 shows a cross-sectional configuration of the imaging lens ofExample 3. The imaging lens of Example 3 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 3, Table 9 shows basic lens data,Table 10 shows specification, Table 11 shows variable surface distances,Table 12 shows aspheric surface coefficients, and FIGS. 8 and 9 showaberration diagrams. In FIG. 8, the upper part shows aberration diagramsin a state where the object at infinity is in focus, and the lower partshows aberration diagrams in a state where the object at the distance of0.7 m (meter) from the object to the image plane Sim is in focus. FIG. 9shows lateral aberration diagram in a state where the object at infinityis in focus.

TABLE 9 Example 3 Sn R D Nd νd θgF  1 −138.62827 2.400 1.54072 47.230.56780  2 58.55723 10.030   3 75.89616 11.800  1.59282 68.62 0.54414  4−105.01257 0.200  5 45.45982 10.800  1.59282 68.62 0.54414  6 399.214430.600  7 44.95362 4.320 1.95906 17.47 0.65993  8 63.84817 0.600  936.12697 5.270 1.78800 47.52 0.55545 10 60.17700 1.800 1.89286 20.360.63944 11 31.65635 4.565 12 177.12407 1.520 1.80809 22.76 0.63073 1327.86122 6.406   14(St) ∞ DD[14] *15  −14.64464 2.550 1.68863 31.200.60109 *16  −18.73058 0.200 17 49.66071 6.450 1.88300 39.22 0.57295 18−32.52200 1.210 1.69895 30.05 0.60174 19 32.52200 0.820 20 42.224288.800 1.88300 39.22 0.57295 21 −28.75400 1.210 1.62005 36.35 0.58602 22−178.14293 DD[22] 23 ∞ 2.850 1.51680 64.20 0.53430 24 ∞ 1.000

TABLE 10 Example 3 f 49.549 FNo. 1.03 2ωmax 31.4

TABLE 11 Example 3 Infinity 0.7 m DD[14] 11.466 7.025 DD[22] 14.40118.842

TABLE 12 Example 3 Sn 15 16 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 5.0823068E−05 3.9661172E−05 A55.6696216E−06 7.3155985E−06 A6 −1.1665918E−06  −1.9241870E−06  A72.3011235E−07 2.0632606E−07 A8 −8.5462646E−09  2.7709406E−08 A9−3.9871990E−09  −6.9926396E−09  A10 5.8946218E−10 −2.2702122E−11  A116.8551648E−12 9.8429055E−11 A12 −7.4371184E−12  −3.5432557E−12  A133.9451971E−13 −7.7218349E−13  A14 3.7621265E−14 4.3918443E−14 A15−4.2785117E−15  3.5209637E−15 A16 −2.5668735E−17  −2.5005394E−16  A171.8252095E−17 −8.7077803E−18  A18 −4.3536351E−19  7.1579377E−19 A19−2.9072588E−20  9.0040531E−21 A20 1.1528202E−21 −8.3059544E−22 

Example 4

FIG. 10 shows a cross-sectional configuration of the imaging lens ofExample 4. The imaging lens of Example 4 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 4, Table 13 shows basic lens data,Table 14 shows specification, Table 15 shows variable surface distances,Table 16 shows aspheric surface coefficients, and FIGS. 11 and 12 showaberration diagrams. In FIG. 11, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 12 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 13 Example 4 Sn R D Nd νd θgF  1 −184.15927 2.400 1.80000 29.840.60178  2 62.61647 4.878  3 98.51388 6.313 1.98613 16.48 0.66558  44034.13252 1.100  5 63.34975 10.200  1.59282 68.62 0.54414  6 −296.070520.200  7 44.03004 10.250  1.59282 68.62 0.54414  8 795.08982 0.200  934.85519 7.910 1.87070 40.73 0.56825 10 121.35104 1.500 1.89286 20.360.63944 11 41.54155 2.500 12 103.47070 1.500 1.85896 22.73 0.62844 1322.43821 7.000   14(St) ∞ DD[14] 15 −23.29314 1.110 1.59270 35.310.59336 16 23.13973 7.642 1.88300 39.22 0.57295 17 −49.13842 0.500 *18 −31.45625 2.200 1.68948 31.02 0.59874 *19  −35.44240 0.100 20 57.702658.669 1.88300 39.22 0.57295 21 −29.44571 1.210 1.59270 35.31 0.59336 22455.30805 DD[22] 23 ∞ 2.850 1.51680 64.20 0.53430 24 ∞ 1.000

TABLE 14 Example 4 f 48.495 FNo. 1.03 2ωmax 32.4

TABLE 15 Example 4 Infinity 0.6 m DD[14] 10.100 5.021 DD[22] 14.40219.481

TABLE 16 Example 4 Sn 18 19 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 −4.1880254E−05  −1.8080969E−05  A52.2277957E−05 1.7658879E−05 A6 −1.0486644E−06  −1.2728716E−06  A7−6.0774700E−07  −2.8821944E−07  A8 6.5534778E−08 3.8775713E−08 A99.8049532E−09 3.2995970E−09 A10 −1.3866580E−09  −5.0968526E−10  A11−9.2054942E−11  −2.6981943E−11  A12 1.6184890E−11 3.7414083E−12 A134.5994752E−13 1.6196819E−13 A14 −1.1024413E−13  −1.4531348E−14  A15−7.7379704E−16  −6.8886559E−16  A16 4.2085620E−16 1.7953337E−17 A17−2.3252064E−18  1.8140969E−18 A18 −7.7399797E−19  5.5970230E−20 A198.4567070E−21 −2.1514981E−21  A20 4.0991440E−22 −1.5749796E−22 

Example 5

FIG. 13 shows a cross-sectional configuration of the imaging lens ofExample 5. The imaging lens of Example 5 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 5, Table 17 shows basic lens data,Table 18 shows specification, Table 19 shows variable surface distances,Table 20 shows aspheric surface coefficients, and FIGS. 14 and 15 showaberration diagrams. In FIG. 14, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 15 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 17 Example 5 Sn R D Nd νd θgF  1 −165.93122 2.400 1.56037 43.680.57006  2 76.27518 8.339  3 203.54358 10.000  1.59522 67.73 0.54426  4−111.87010 1.010  5 56.74170 5.365 1.89286 20.36 0.63944  6 102.450840.200  7 44.31471 10.250  1.59522 67.73 0.54426  8 292.61942 0.200  932.85510 8.595 1.69253 56.87 0.54266 10 115.66155 1.500 1.78472 25.680.61052 11 31.63618 2.819 12 63.52660 1.500 1.89286 20.36 0.63944 1323.88347 7.000   14(St) ∞ DD[14] *15  −16.34570 2.837 1.68948 31.020.59874 *16  −22.88973 0.200 17 45.14005 6.141 1.90043 37.37 0.57720 18−33.79047 1.110 1.70834 29.58 0.59931 19 33.20670 1.120 20 51.980528.500 1.90043 37.37 0.57720 21 −22.44701 1.210 1.60763 37.24 0.58209 22−201.05993 DD[22] 23 ∞ 2.850 1.54763 54.98 0.55247 24 ∞ 1.000

TABLE 18 Example 5 f 50.617 FNo. 1.03 2ωmax 31.4

TABLE 19 Example 5 Infinity 0.6 m DD[14] 11.000 5.612 DD[22] 15.43620.824

TABLE 20 Example 5 Sn 15 16 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 3.1181867E−05 2.6530803E−05 A51.4794096E−05 1.5226995E−05 A6 −2.8122797E−06  −3.5186055E−06  A78.9003214E−08 2.0389209E−07 A8 6.9213577E−08 7.3115649E−08 A9−8.7233682E−09  −1.1688257E−08  A10 −8.1799110E−10  −5.0238456E−10  A111.9725575E−10 1.9915512E−10 A12 3.0890969E−12 −2.4972651E−12  A13−2.3953381E−12  −1.7930323E−12  A14 4.0298515E−14 6.6348784E−14 A151.6625829E−14 9.1585232E−15 A16 −5.7273231E−16  −4.6481540E−16  A17−6.1842548E−17  −2.5090883E−17  A18 2.7969524E−18 1.4869080E−18 A199.5479576E−20 2.8685321E−20 A20 −4.9925629E−21  −1.8543937E−21 

Example 6

FIG. 16 shows a cross-sectional configuration of the imaging lens ofExample 6. The imaging lens of Example 6 consists of, in order from theobject side, a first lens group G1 that has a positive refractive power,an aperture stop St, and a second lens group G2 that has a positiverefractive power. During focusing from the object at infinity to theclosest object, the first lens group G1 remains stationary with respectto the image plane Sim, and the second lens group G2 moves to the objectside along the optical axis Z. The first lens group G1 consists of eightlenses L1 a to L1 h in order from the object side. The second lens groupG2 consists of five lenses L2 a to L2 e in order from the object side.

Regarding the imaging lens of Example 6, Table 21 shows basic lens data,Table 22 shows specification, Table 23 shows variable surface distances,Table 24 shows aspheric surface coefficients, and FIGS. 17 and 18 showaberration diagrams. In FIG. 17, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 18 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 21 Example 6 Sn R D Nd νd θgF  1 −247.95976 2.800 1.77791 26.100.61461  2 75.89689 11.010   3 114.39503 7.000 1.92286 18.90 0.64960  4−837.42367 0.100  5 69.26549 11.000  1.58525 61.72 0.54210  6 196.031970.100  7 84.81564 7.038 1.53775 74.70 0.53936  8 1034.21503 0.100  991.91092 5.000 1.53775 74.70 0.53936 10 177.41757 0.100 11 33.3027912.000  1.88300 39.22 0.57295 12 −424.49645 1.510 1.72186 28.91 0.6011313 61.07419 1.500 14 98.63832 1.500 1.91717 19.14 0.63501 15 21.081307.000   16(St) ∞ DD[16] 17 −22.42941 1.100 1.58780 39.22 0.57813 1823.14403 7.400 1.88300 39.22 0.57295 19 −31.61388 1.000 *20  −33.946411.800 1.61724 36.28 0.58403 *21  173.48601 0.100 22 47.71113 7.2711.81834 46.17 0.55821 23 −26.72012 1.210 1.69584 30.30 0.60324 24−56.34422 DD[24] 25 ∞ 2.850 1.51680 64.20 0.53430 26 ∞ 1.000

TABLE 22 Example 6 f 48.498 FNo. 1.03 2ωmax 32.6

TABLE 23 Example 6 Infinity 0.6 m DD[16] 10.100 4.816 DD[24] 14.40019.684

TABLE 24 Example 6 Sn 20 21 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 −2.3773046E−05  3.0929722E−06 A55.6674484E−06 4.8487684E−06 A6 5.6970844E−08 −5.0456910E−07  A7−1.9176909E−07  1.5258010E−08 A8 1.9626233E−08 6.7914018E−09 A92.9049337E−09 −1.5524880E−09  A10 −6.6057808E−10  −1.1339723E−11  A11−1.9889473E−11  2.4115890E−11 A12 1.0577029E−11 −4.6114184E−13  A137.5098137E−15 −1.8660180E−13  A14 −9.7929627E−14  3.8327989E−15 A157.5328476E−16 7.9224149E−16 A16 5.3398130E−16 −7.7601860E−18  A17−4.2992770E−18  −1.7504256E−18  A18 −1.5949215E−18  −2.1972718E−20  A197.7287369E−21 1.5807498E−21 A20 2.0144963E−21 7.7734912E−23

Example 7

FIG. 19 shows a cross-sectional configuration of the imaging lens ofExample 7. The imaging lens of Example 7 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of eight lenses L1 a to L1 h in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 7, Table 25 shows basic lens data,Table 26 shows specification, Table 27 shows variable surface distances,Table 28 shows aspheric surface coefficients, and FIGS. 20 and 21 showaberration diagrams. In FIG. 20, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 21 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 25 Example 7 Sn R D Nd νd θgF  1 −204.30501 2.800 1.81294 24.350.61887  2 81.96794 13.010   3 137.60012 7.000 2.10420 17.02 0.66311  4−656.31103 3.750  5 69.54614 12.000  1.57265 62.21 0.54137  6 267.604810.193  7 88.85695 9.422 1.43875 94.66 0.53402  8 −2937.87944 0.100  996.07701 5.000 1.43875 94.66 0.53402 10 181.83582 0.100 11 33.1715712.000  1.88300 39.22 0.57295 12 −374.98026 1.510 1.76530 26.82 0.6071313 66.58003 1.500 14 97.44593 1.500 1.96720 17.42 0.64384 15 21.584637.000   16(St) ∞ DD[16] 17 −22.85203 1.100 1.56026 43.70 0.57003 1822.46642 7.400 1.88300 39.22 0.57295 19 −31.83440 1.000 *20  −30.583261.800 1.66113 32.78 0.59162 *21  340.35421 0.100 22 55.88143 6.4861.81271 42.14 0.56732 23 −26.29030 1.210 1.70642 29.68 0.60465 24−49.33676 DD[24] 25 ∞ 2.850 1.51680 64.20 0.53430 26 ∞ 1.000

TABLE 26 Example 7 f 48.220 FNo. 1.04 2ωmax 32.8

TABLE 27 Example 7 Infinity 0.6 m DD[16] 10.100 4.858 DD[24] 14.97320.215

TABLE 28 Example 7 Sn 20 21 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 −2.1813953E−05  5.6632078E−06 A55.5899615E−06 4.4402595E−06 A6 8.3363623E−08 −4.7071845E−07  A7−1.9184059E−07  1.5982530E−08 A8 1.9586298E−08 6.7572477E−09 A92.8981856E−09 −1.5590421E−09  A10 −6.6105638E−10  −1.1726148E−11  A11−1.9888631E−11  2.4116692E−11 A12 1.0581175E−11 −4.5950671E−13  A138.0018964E−15 −1.8648724E−13  A14 −9.7926487E−14  3.8358049E−15 A157.5055780E−16 7.9215688E−16 A16 5.3398130E−16 −7.7662214E−18  A17−4.2992770E−18  −1.7496474E−18  A18 −1.5949215E−18  −2.1852378E−20  A197.7287369E−21 1.5557319E−21 A20 2.0144963E−21 7.8155637E−23

Example 8

FIG. 22 shows a cross-sectional configuration of the imaging lens ofExample 8. The imaging lens of Example 8 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 8, Table 29 shows basic lens data,Table 30 shows specification, Table 31 shows variable surface distances,Table 32 shows aspheric surface coefficients, and FIGS. 23 and 24 showaberration diagrams. In FIG. 23, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 24 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 29 Example 8 Sn R D Nd νd θgF  1 −1250.00000 2.400 1.50911 53.290.55329  2 58.56667 12.004   3 63.53662 10.300  1.55032 75.50 0.54001  4−324.18577 1.010  5 91.24308 4.145 1.55032 75.50 0.54001  6 237.796010.200  7 41.36102 10.250  1.59282 68.62 0.54414  8 108.29456 0.200  935.06677 7.900 2.00069 25.46 0.61364 10 76.31696 0.806 11 90.22442 1.5001.78880 28.43 0.60092 12 28.87926 2.968 13 53.65263 1.500 1.89286 20.360.63944 14 23.13445 7.000   15(St) ∞ DD[15] *16  −16.70584 1.943 1.6894831.02 0.59874 *17  −24.50468 0.200 18 44.48608 6.995 1.88300 39.220.57295 19 −26.79392 1.110 1.71036 29.48 0.59958 20 33.02652 1.005 2148.60027 9.237 1.85150 40.78 0.56958 22 −19.88726 1.210 1.56738 42.370.57237 23 −131.23867 DD[23] 24 ∞ 2.850 1.51680 64.20 0.53430 25 ∞ 1.000

TABLE 30 Example 8 f 51.521 FNo. 1.03 2ωmax 31.0

TABLE 31 Example 8 Infinity 0.6 m DD[15] 11.000 5.534 DD[23] 15.40120.867

TABLE 32 Example 8 Sn 16 17 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 7.0570380E−05 6.6014243E−05 A51.9198543E−05 1.9606733E−05 A6 −3.3289534E−06  −4.2582967E−06  A7−9.0333134E−08  1.4153915E−07 A8 9.0099971E−08 9.0936965E−08 A9−4.1396511E−09  −1.1106603E−08  A10 −1.4390577E−09  −8.1411034E−10  A111.2641084E−10 1.9638299E−10 A12 1.3445189E−11 1.0722851E−12 A13−1.7282916E−12  −1.7929595E−12  A14 −6.2059351E−14  3.9257132E−14 A151.2881202E−14 9.2275563E−15 A16 2.3758855E−17 −3.3269509E−16  A17−5.0325955E−17  −2.5409216E−17  A18 9.0421501E−19 1.1130994E−18 A198.0548323E−20 2.9170042E−20 A20 −2.4717980E−21  −1.3898997E−21 

Example 9

FIG. 25 shows a cross-sectional configuration of the imaging lens ofExample 9. The imaging lens of Example 9 consists of, in order from theobject side, the first lens group G1 that has a positive refractivepower, the aperture stop St, and the second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of seven lenses L1 a to L1 g in order from the object side. Thesecond lens group G2 consists of five lenses L2 a to L2 e in order fromthe object side.

Regarding the imaging lens of Example 9, Table 33 shows basic lens data,Table 34 shows specification, Table 35 shows variable surface distances,Table 36 shows aspheric surface coefficients, and FIGS. 26 and 27 showaberration diagrams. In FIG. 26, the upper part shows aberrationdiagrams in a state where the object at infinity is in focus, and thelower part shows aberration diagrams in a state where the object at thedistance of 0.6 m (meter) from the object to the image plane Sim is infocus. FIG. 27 shows lateral aberration diagram in a state where theobject at infinity is in focus.

TABLE 33 Example 9 Sn R D Nd νd θgF  1 −193.76114 2.400 1.54760 46.080.56589  2 75.97796 9.081  3 189.01581 10.000  1.49700 81.61 0.53887  4−105.13621 1.010  5 56.49917 5.721 1.92119 23.96 0.62025  6 104.364060.200  7 43.70727 10.385  1.49700 81.61 0.53887  8 340.80096 0.200  932.58246 9.094 1.75819 43.78 0.56631 10 73.72282 1.500 1.78472 25.680.61052 11 32.68245 2.542 12 61.75401 1.500 1.89286 20.36 0.63944 1322.41400 7.000   14(St) ∞ DD[14] *15  −16.41866 2.693 1.68948 31.020.59874 *16  −22.85517 0.200 17 45.64284 6.105 1.88300 39.22 0.57295 18−33.87303 1.110 1.68877 30.80 0.59625 19 33.14697 1.132 20 52.162268.770 1.88300 39.22 0.57295 21 −21.44050 1.210 1.59203 38.80 0.57897 22−202.15701 DD[22] 23 ∞ 2.850 1.51680 64.20 0.53430 24 ∞ 1.000

TABLE 34 Example 9 f 51.018 FNo. 1.03 2ωmax 31.2

TABLE 35 Example 9 Infinity 0.6 m DD[14] 11.000 5.539 DD[22] 15.40120.862

TABLE 36 Example 9 Sn 15 16 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 2.5050662E−05 2.1927553E−05 A51.6399123E−05 1.6962214E−05 A6 −2.7037336E−06  −3.5614573E−06  A72.2716407E−08 1.6637583E−07 A8 7.0481328E−08 7.6462842E−08 A9−7.0934969E−09  −1.1129036E−08  A10 −9.1743883E−10  −5.7804163E−10  A111.7293397E−10 1.9360903E−10 A12 5.1834973E−12 −1.4806257E−12  A13−2.1727289E−12  −1.7572338E−12  A14 1.7187231E−14 5.7682678E−14 A151.5404695E−14 9.0145899E−15 A16 −4.2947569E−16  −4.1936383E−16  A17−5.8157492E−17  −2.4764768E−17  A18 2.3258567E−18 1.3542989E−18 A199.0773374E−20 2.8368189E−20 A20 −4.3526649E−21  −1.6904315E−21 

Example 10

FIG. 28 shows a cross-sectional configuration of the imaging lens ofExample 10. The imaging lens of Example 10 consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, an aperture stop St, a second lens group G2 having a negativerefractive power, and a third lens group G3 having a positive refractivepower. During focusing from the object at infinity to the closestobject, the first lens group G1 and the third lens group G3 remainstationary with respect to the image plane Sim, and the second lensgroup G2 moves to the image side along the optical axis Z. The firstlens group G1 consists of seven lenses L1 a to L1 g in order from theobject side. The second lens group G2 consists of four lenses L2 a to L2d in order from the object side. The third lens group G3 consists offive lenses L3 a to L3 e in order from the object side.

Regarding the imaging lens of Example 10, Table 37 shows basic lensdata, Table 38 shows specification, Table 39 shows variable surfacedistances, and FIGS. 29 and 30 shows aberration diagrams. In FIG. 29,the upper part shows aberration diagrams in a state where the object atinfinity is in focus, and the lower part shows aberration diagrams in astate where the object at the distance of 0.7 m (meter) from the objectto the image plane Sim is in focus. FIG. 30 shows lateral aberrationdiagram in a state where the object at infinity is in focus.

TABLE 37 Example 10 Sn R D Nd νd θgF  1 272.44778 3.300 2.05090 26.940.60519  2 1081.40696 0.100  3 89.65014 3.000 1.59282 68.62 0.54414  4152.15669 0.100  5 74.09242 6.000 1.59282 68.62 0.54414  6 263.349770.100  7 107.02621 1.500 1.85896 22.73 0.62844  8 78.42749 10.010 1.76212 31.60 0.59550  9 −175.82899 1.000 10 −144.21433 1.500 1.8589622.73 0.62844 11 80.87758 4.510 1.56883 56.36 0.54890 12 716.45491 5.217  13(St) ∞ DD[13] 14 −38.44224 1.000 1.87904 40.10 0.56811 15 130.292496.010 1.59410 60.47 0.55516 16 −33.25476 0.600 17 −351.00941 4.0002.00272 19.32 0.64514 18 −45.80501 1.500 1.64173 39.35 0.57903 1936.04598 DD[19] 20 43.30755 7.389 1.59522 67.73 0.54426 21 −236.349550.100 22 90.49741 7.652 1.83481 42.72 0.56486 23 −46.09199 1.360 1.6727032.10 0.59891 24 27.92315 4.075 25 30.74850 9.035 1.65463 48.36 0.5620826 −201.70415 2.100 27 −51.13607 1.350 1.48749 70.44 0.53062 28 76.1289021.401  29 ∞ 2.850 1.51680 64.20 0.53430 30 ∞ 1.000

TABLE 38 Example 10 f 87.302 FNo. 1.86 2ωmax 18.6

TABLE 39 Example 10 Infinity 0.7 m DD[13] 5.000 16.962 DD[19] 15.7023.740

Example 11

FIG. 31 shows a cross-sectional configuration of the imaging lens ofExample 11. The imaging lens of Example 11 consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, an aperture stop St, a second lens group G2 having a negativerefractive power, and a third lens group G3 having a positive refractivepower. During focusing from the object at infinity to the closestobject, the first lens group G1 and the third lens group G3 remainstationary with respect to the image plane Sim, and the second lensgroup G2 moves to the image side along the optical axis Z. The firstlens group G1 consists of eight lenses L1 a to L1 h in order from theobject side. The second lens group G2 consists of four lenses L2 a to L2d in order from the object side. The third lens group G3 consists offive lenses L3 a to L3 e in order from the object side.

Regarding the imaging lens of Example 11, Table 40 shows basic lensdata, Table 41 shows specification, Table 42 shows variable surfacedistances, and FIGS. 32 and 33 shows aberration diagrams. In FIG. 32,the upper part shows aberration diagrams in a state where the object atinfinity is in focus, and the lower part shows aberration diagrams in astate where the object at the distance of 0.8 m (meter) from the objectto the image plane Sim is in focus. FIG. 33 shows lateral aberrationdiagram in a state where the object at infinity is in focus.

TABLE 40 Example 11 Sn R D Nd νd θgF  1 −386.94657 1.800 1.69680 55.530.54341  2 119.46581 2.500  3 207.26394 4.000 1.95375 32.32 0.59015  4−238.96341 0.100  5 76.64894 4.500 1.59522 67.73 0.54426  6 248.424690.100  7 63.92071 5.500 1.43875 94.66 0.53402  8 216.59149 0.100  9107.16236 1.500 1.85025 30.05 0.59797 10 85.24799 7.998 1.65412 39.680.57378 11 −205.11243 1.000 12 −197.70982 1.500 1.92119 23.96 0.62025 1390.62875 4.510 1.45860 90.19 0.53516 14 −30275.61759 8.130   15(St) ∞DD[15] 16 −43.49420 1.000 1.89190 37.13 0.57813 17 185.12129 6.0101.77250 49.60 0.55212 18 −44.59399 0.600 19 −428.71303 4.000 2.1042017.02 0.66311 20 −76.05920 1.500 1.58144 40.75 0.57757 21 37.00980DD[21] 22 36.00466 5.851 1.59522 67.73 0.54426 23 −124.44012 0.100 24829.97224 5.140 1.90043 37.37 0.57720 25 −51.93826 1.360 1.67270 32.100.59891 26 28.10820 3.300 27 34.48127 9.174 1.77250 49.60 0.55212 28−110.39811 2.231 29 −38.11168 1.350 1.48749 70.44 0.53062 30 89.5787121.429  31 ∞ 2.850 1.51680 64.20 0.53430 32 ∞ 1.000

TABLE 41 Example 11 f 79.213 FNo. 1.65 2ωmax 20.2

TABLE 42 Example 11 Infinity 0.8 m DD[15] 5.043 18.069 DD[21] 14.8641.838

Example 12

FIG. 34 shows a cross-sectional configuration of the imaging lens ofExample 12. The imaging lens of Example 12 consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, an aperture stop St, a second lens group G2 having a negativerefractive power, and a third lens group G3 having a positive refractivepower. During focusing from the object at infinity to the closestobject, the first lens group G1 and the third lens group G3 remainstationary with respect to the image plane Sim, and the second lensgroup G2 moves to the image side along the optical axis Z. The firstlens group G1 consists of eight lenses L1 a to L1 h in order from theobject side. The second lens group G2 consists of four lenses L2 a to L2d in order from the object side. The third lens group G3 consists offive lenses L3 a to L3 e in order from the object side.

Regarding the imaging lens of Example 12, Table 43 shows basic lensdata, Table 44 shows specification, Table 45 shows variable surfacedistances, and FIGS. 35 and 36 shows aberration diagrams. In FIG. 35,the upper part shows aberration diagrams in a state where the object atinfinity is in focus, and the lower part shows aberration diagrams in astate where the object at the distance of 0.7 m (meter) from the objectto the image plane Sim is in focus. FIG. 36 shows lateral aberrationdiagram in a state where the object at infinity is in focus.

TABLE 43 Example 12 Sn R D Nd νd θgF  1 −291.68052 1.800 1.64769 33.790.59393  2 99.99894 2.500  3 177.53930 4.000 1.92119 23.96 0.62025  4−250.63993 0.100  5 83.49241 3.500 1.59522 67.73 0.54426  6 315.246880.100  7 65.26695 5.500 1.55032 75.50 0.54001  8 230.27246 0.100  9117.55484 1.500 2.00069 25.46 0.61364 10 89.18435 10.010  1.67300 38.260.57580 11 −205.86865 1.000 12 −214.55358 1.500 1.85896 22.73 0.62844 1381.16463 4.510 1.62299 58.16 0.54589 14 301.17897 7.667   15(St) ∞DD[15] 16 −44.85924 1.000 1.89190 37.13 0.57813 17 78.25190 6.0101.72916 54.68 0.54451 18 −44.95132 0.600 19 −344.73789 4.000 1.9459517.98 0.65460 20 −48.43416 1.500 1.58144 40.75 0.57757 21 36.97488DD[21] 22 38.40711 5.751 1.59522 67.73 0.54426 23 −82.40638 0.100 24−707.34003 5.905 1.85150 40.78 0.56958 25 −45.35298 1.360 1.67270 32.100.59891 26 27.74475 1.726 27 31.49767 9.688 1.80400 46.53 0.55775 28−172.72812 2.100 29 −40.02478 1.350 1.48749 70.44 0.53062 30 129.3212821.402  31 ∞ 2.850 1.51680 64.20 0.53430 32 ∞ 1.000

TABLE 44 Example 12 f 77.634 FNo. 1.65 2ωmax 20.8

TABLE 45 Example 12 Infinity 0.7 m DD[15] 5.000 19.027 DD[21] 14.9080.881

Example 13

FIG. 37 shows a cross-sectional configuration of the imaging lens ofExample 13. The imaging lens of Example 13 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, and a second lens group G2 that has a positive refractive power.During focusing from the object at infinity to the closest object, thefirst lens group G1 remains stationary with respect to the image planeSim, and the second lens group G2 moves to the object side along theoptical axis Z. The first lens group G1 consists of eight lenses L1 a toL1 h in order from the object side. The second lens group G2 consists oflenses L2 a to L2 c, an aperture stop St, and lenses L2 d to L2 g inorder from the object side.

Regarding the imaging lens of Example 13, Table 46 shows basic lensdata, Table 47 shows specification, Table 48 shows variable surfacedistances, Table 49 shows aspheric surface coefficients, and FIGS. 38and 39 show aberration diagrams. In FIG. 38, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.4 m (meter) from the object to the image plane Simis in focus. FIG. 39 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 46 Example 13 Sn R D Nd νd θgF  1 −80.28635 2.000 1.48749 70.240.53007  2 42.98733 13.000   3 −63.79046 1.860 1.62004 36.26 0.58800  451.39741 12.441  1.88299 40.78 0.56829  5 −144.73231 0.100  6 176.279197.877 2.00069 25.46 0.61364  7 −160.05852 0.100  8 24017.51177 11.145 1.49700 81.54 0.53748  9 −53.46758 2.020 1.95906 17.47 0.65993 10−141.76150 0.100 11 73.80784 6.228 1.43875 94.66 0.53402 12 −6705.694760.100 13 135.56611 4.200 1.49700 81.54 0.53748 14 188.15073 DD[14] 1548.95259 5.513 1.95906 17.47 0.65993 16 205.45635 0.253 17 25.659358.918 1.59282 68.62 0.54414 18 −442.23226 1.200 1.80809 22.76 0.63073 1917.92257 5.504   20(St) ∞ 5.000 *21  −17.88285 1.500 1.68948 31.020.59874 *22  −49.72259 0.500 23 213.02720 6.649 1.81600 46.62 0.55682 24−19.33525 1.120 1.62004 36.26 0.58800 25 47.67656 6.689 1.88299 40.780.56829 26 −31.38846 DD[26] 27 ∞ 2.850 1.51680 64.20 0.53430 28 ∞ 1.000

TABLE 47 Example 13 f 32.024 FNo. 1.03 2ωmax 49.0

TABLE 48 Example 13 Infinity 0.4 m DD[14] 5.524 1.833 DD[26] 14.09817.789

TABLE 49 Example 13 Sn 21 22 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 1.7715606E−04 1.7642986E−04 A51.7074166E−05 1.6476812E−05 A6 −5.3189612E−06  −4.6629565E−06  A7−1.7052372E−07  −2.6282483E−07  A8 1.0629596E−07 1.1534278E−07 A93.7804819E−10 −2.9531996E−10  A10 −1.7627478E−09  −1.9368547E−09  A113.7456752E−11 8.2583641E−11 A12 2.1780336E−11 1.9811305E−11 A13−1.0619291E−12  −1.3990529E−12  A14 −1.6070128E−13  −1.1461723E−13  A151.2952078E−14 1.1207794E−14 A16 4.9200989E−16 2.9951674E−16 A17−7.4222889E−17  −4.5040584E−17  A18 6.6519028E−19 5.5182976E−20 A191.6312319E−19 7.2914615E−20 A20 −5.4198359E−21  −1.3034388E−21 

Example 14

FIG. 40 shows a cross-sectional configuration of the imaging lens ofExample 14. The imaging lens of Example 14 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, and a second lens group G2 that has a positive refractive power.During focusing from the object at infinity to the closest object, thefirst lens group G1 remains stationary with respect to the image planeSim, and the second lens group G2 moves to the object side along theoptical axis Z. The first lens group G1 consists of eight lenses L1 a toL1 h in order from the object side. The second lens group G2 consistsof, in order from the object side, lenses L2 a to L2 c, an aperture stopSt, and lenses L2 d to L2 f.

Regarding the imaging lens of Example 14, Table 50 shows basic lensdata, Table 51 shows specification, Table 52 shows variable surfacedistances, Table 53 shows aspheric surface coefficients, and FIGS. 41and 42 show aberration diagrams. In FIG. 41, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.3 m (meter) from the object to the image plane Simis in focus. FIG. 42 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 50 Example 14 Sn R D Nd νd θgF  1 −741.84965 4.557 2.00001 16.350.64993  2 −133.27267 2.137  3 −88.69549 2.000 1.51957 51.33 0.55675  430.12135 17.951   5 −43.59777 1.860 1.72220 28.89 0.60118  6 50.0795114.509  1.99166 26.42 0.61104  7 −73.94447 0.200  8 102.81602 12.918 1.72183 55.41 0.54271  9 −47.50103 2.020 1.96573 16.71 0.64633 10−188.35959 0.100 11 282.52887 4.513 1.43875 94.66 0.53402 12 −146.673610.010 13 51.37757 3.531 1.59522 67.73 0.54426 14 63.46607 DD[14] 1549.82440 5.000 2.00001 15.00 0.65515 16 197.53926 0.250 17 27.636159.109 1.59522 67.73 0.54426 18 −134.79322 1.550 1.85370 22.31 0.62213 1918.23355 5.500   20(St) ∞ 5.487 21 −18.30655 1.500 1.63029 39.17 0.5792522 −48.92302 5.529 1.48984 65.39 0.53509 23 −24.64229 0.100 *24 56.89240 6.000 1.79341 48.66 0.55129 *25  −36.65031 DD[25] 26 ∞ 2.8501.51680 64.20 0.53430 27 ∞ 1.000

TABLE 51 Example 14 f 29.079 FNo. 1.03 2ωmax 53.2

TABLE 52 Example 14 Infinity 0.3 m DD[14] 6.500 1.921 DD[25] 16.34220.921

TABLE 53 Example 14 Sn 24 25 KA  1.0000000E+00 1.0000000E+00 A4−1.6809135E−06 8.5774318E−06 A6 −2.1517689E−07 −2.0857403E−07  A8 9.2942401E−09 6.7208947E−09 A10 −2.1073323E−10 −1.2334691E−10  A12 2.8305897E−12 1.3706654E−12 A14 −2.3236997E−14 −9.4138699E−15  A16 1.1475262E−16 3.9270429E−17 A18 −3.1366558E−19 −9.1668061E−20  A20 3.6536989E−22 9.2574233E−23

Example 15

FIG. 43 shows a cross-sectional configuration of the imaging lens ofExample 15. The imaging lens of Example 15 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, and a second lens group G2 that has a positive refractive power.During focusing from the object at infinity to the closest object, thefirst lens group G1 remains stationary with respect to the image planeSim, and the second lens group G2 moves to the object side along theoptical axis Z. The first lens group G1 consists of eight lenses L1 a toL1 h in order from the object side. The second lens group G2 consists oflenses L2 a to L2 c, an aperture stop St, and lenses L2 d to L2 g inorder from the object side.

Regarding the imaging lens of Example 15, Table 54 shows basic lensdata, Table 55 shows specification, Table 56 shows variable surfacedistances, Table 57 shows aspheric surface coefficients, and FIGS. 44and 45 show aberration diagrams. In FIG. 44, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.3 m (meter) from the object to the image plane Simis in focus. FIG. 45 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 54 Example 15 Sn R D Nd νd θgF  1 642.95860 5.882 2.00001 16.890.64786  2 −164.66697 1.863  3 −99.52183 2.000 1.61064 54.41 0.55296  433.83357 15.951  5 −47.68180 1.860 1.70668 31.21 0.59581  6 51.0637513.761 1.98542 25.79 0.61339  7 −87.22549 0.200  8 126.67025 12.3251.72259 55.37 0.54271  9 −47.54495 2.020 1.97455 17.92 0.64243 10−275.27420 0.100 11 171.98328 5.821 1.43875 94.66 0.53402 12 −113.397890.010 13 46.43027 5.041 1.59522 67.73 0.54426 14 84.61748 DD[14] 1555.77297 4.000 2.00000 15.00 0.65515 16 202.80478 0.605 17 27.637158.988 1.58689 61.66 0.54186 18 −134.09655 1.550 1.85789 22.11 0.62292 1919.09448 5.638   20(St) ∞ 5.927 *21  −28.03700 1.500 1.89872 28.110.60520 *22  −44.46753 1.250 23 −96.25411 6.671 1.74032 53.97 0.54394 24−23.20962 0.500 25 63.33337 6.000 1.90048 37.95 0.57345 26 −32.845081.310 1.47999 58.75 0.54320 27 33.51612 DD[27] 28 ∞ 2.850 1.51680 64.200.53430 29 ∞ 1.000

TABLE 55 Example 15 f 29.906 FNo. 1.03 2ωmax 51.4

TABLE 56 Example 15 Infinity 0.3 m DD[14] 6.500 1.468 DD[27] 11.90016.932

TABLE 57 Example 15 Sn 21 22 KA  1.0000000E+00  1.0000000E+00 A4−5.0827829E−05 −2.1426467E−05 A6 −1.1853379E−07 −4.7548185E−08 A8 9.4795512E−09  5.2403072E−09 A10 −2.7750209E−10 −1.0968658E−10 A12 5.8490730E−12  2.0277440E−12 A14 −7.6027021E−14 −2.5419242E−14 A16 5.7225628E−16  1.8641103E−16 A18 −2.2972054E−18 −7.2476475E−19 A20 3.8030548E−21  1.1546366E−21

Example 16

FIG. 46 shows a cross-sectional configuration of the imaging lens ofExample 16. The imaging lens of Example 16 consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, a second lens group G2 having a positive refractive power, and athird lens group G3 having a negative refractive power. During focusingfrom the object at infinity to the closest object, the first lens groupG1 and the third lens group G3 remain stationary with respect to theimage plane Sim, and the second lens group G2 moves to the object sidealong the optical axis Z. The first lens group G1 consists of sevenlenses L1 a to L1 g in order from the object side. The second lens groupG2 consists of, in order from the object side, lenses L2 a to L2 c, anaperture stop St, and lenses L2 d to L2 f. The third lens group G3consists of two lenses L3 a and L3 b in order from the object side.

Regarding the imaging lens of Example 16, Table 58 shows basic lensdata, Table 59 shows specification, Table 60 shows variable surfacedistances, Table 61 shows aspheric surface coefficients, and FIGS. 47and 48 show aberration diagrams. In FIG. 47, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.3 m (meter) from the object to the image plane Simis in focus. FIG. 48 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 58 Example 16 Sn R D Nd νd θgF  1 −297.13714 7.166 1.87070 40.730.56825  2 −85.86719 1.000  3 −73.16221 2.000 1.74077 27.79 0.60961  442.66024 7.413  5 392.24356 6.462 1.87070 40.73 0.56825  6 −146.019204.000  7 −66.16556 1.860 1.72825 28.46 0.60772  8 51.18899 11.8662.10420 17.02 0.66311  9 −245.64485 0.200 10 77.22649 15.828 1.8830040.80 0.56557 11 −47.49919 2.020 1.98613 16.48 0.66558 12 −198.94323DD[12] 13 55.79899 6.000 1.92286 20.88 0.63900 14 1076.94076 0.250 1530.39757 10.286 1.59410 60.47 0.55516 16 −49.75521 1.550 1.92286 20.880.63900 17 20.04359 5.500   18(St) ∞ 5.642 19 −22.24985 1.510 1.5927035.31 0.59336 20 30.44450 8.452 1.90043 37.37 0.57668 21 −37.69952 0.270*22  87.14518 3.500 1.83481 42.72 0.56486 *23  −62.14252 DD[23] 24−134.06447 3.010 1.64000 60.08 0.53704 25 −34.88724 1.000 1.65412 39.680.57378 26 −129.28425 12.064 27 ∞ 2.850 1.51680 64.20 0.53430 28 ∞ 1.000

TABLE 59 Example 16 f 33.489 FNo. 1.03 2ωmax 46.8

TABLE 60 Example 16 Infinity 0.3 m DD[12] 6.714 0.856 DD[23] 2.000 7.858

TABLE 61 Example 16 Sn 22 23 KA  1.0000000E+00  1.0000000E+00 A4−5.8591082E−06  2.8872810E−06 A6  8.0450854E−09 −1.4218337E−08 A8−1.8982768E−10  4.2017521E−11 A10  6.8830323E−13 −2.5968320E−13 A12−2.8216339E−15 −1.0662872E−15

Example 17

FIG. 49 shows a cross-sectional configuration of the imaging lens ofExample 17. The imaging lens of Example 17 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, and a second lens group G2 that has a positive refractive power.During focusing from the object at infinity to the closest object, thefirst lens group G1 remains stationary with respect to the image planeSim, and the second lens group G2 moves to the object side along theoptical axis Z. The first lens group G1 consists of nine lenses L1 a toL1 i in order from the object side. The second lens group G2 consists oflenses L2 a to L2 c, an aperture stop St, and lenses L2 d to L2 g inorder from the object side.

Regarding the imaging lens of Example 17, Table 62 shows basic lensdata, Table 63 shows specification, Table 64 shows variable surfacedistances, Table 65 shows aspheric surface coefficients, and FIGS. 50and 51 show aberration diagrams. In FIG. 50, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.4 m (meter) from the object to the image plane Simis in focus. FIG. 51 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 62 Example 17 Sn R D Nd νd θgF  1 −336.27458 2.200 1.48749 70.240.53007  2 38.98761 15.631  3 −46.53554 2.210 1.59551 39.24 0.58043  4249.77972 5.766 1.88300 39.22 0.57295  5 −160.59902 0.800  6 276.629488.350 2.00069 25.46 0.61364  7 −81.36890 3.916  8 −63.06549 2.2101.69895 30.13 0.60298  9 135.70322 3.841 1.88300 39.22 0.57295 10422.33573 1.500 11 102.34565 15.415 1.43875 94.66 0.53402 12 −44.716982.200 1.85896 22.73 0.62844 13 −77.19256 0.100 14 101.83391 9.3111.59282 68.62 0.54414 15 −119.76934 DD[15] 16 69.07462 5.899 1.9590617.47 0.65993 17 449.86569 0.600 18 33.09295 10.662 1.59282 68.620.54414 19 −150.72672 1.700 1.85896 22.73 0.62844 20 26.86774 6.577  21(St) ∞ 8.310 *22  −28.92910 1.800 1.68948 31.02 0.59874 *23 419.15250 1.784 24 124.99078 6.834 1.88300 39.22 0.57295 25 −19.938921.220 1.59270 35.31 0.59336 26 40.55156 6.493 1.87070 40.73 0.56825 27−53.64933 DD[27] 28 ∞ 2.850 1.51680 64.20 0.53430 29 ∞ 1.000

TABLE 63 Example 17 f 32.299 FNo. 1.03 2ωmax 49.0

TABLE 64 Example 17 Infinity 0.4 m DD[15] 5.583 1.508 DD[27] 14.46318.538

TABLE 65 Example 17 Sn 22 23 KA 1.0000000E+00 1.0000000E+00 A30.0000000E+00 0.0000000E+00 A4 3.5406543E−05 4.9366505E−05 A57.0264041E−06 7.9379491E−06 A6 −1.1816569E−06  −1.4343119E−06  A7−2.2756224E−07  −2.0060437E−07  A8 3.4450831E−08 4.3102131E−08 A95.4529188E−09 3.4605387E−09 A10 −8.2702494E−10  −9.3263727E−10  A11−8.7833902E−11  −3.7283303E−11  A12 1.3514381E−11 1.3092859E−11 A138.9890230E−13 2.4405774E−13 A14 −1.4076774E−13  −1.1755255E−13  A15−5.5890568E−15  −9.1931741E−16  A16 8.9135105E−16 6.5486383E−16 A171.9220049E−17 1.7211209E−18 A18 −3.1226127E−18  −2.0673300E−18  A19−2.7989666E−20  −1.0111723E−21  A20 4.6368363E−21 2.8305920E−21

Example 18

FIG. 52 shows a cross-sectional configuration of the imaging lens ofExample 18. The imaging lens of Example 18 consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, an aperture stop St, a second lens group G2 having a positiverefractive power, and a third lens group G3 having a negative refractivepower. During focusing from the object at infinity to the closestobject, the first lens group G1 and the third lens group G3 remainstationary with respect to the image plane Sim, and the second lensgroup G2 moves to the object side along the optical axis Z. The firstlens group G1 consists of thirteen lenses L1 a to L1 m in order from theobject side. The second lens group G2 consists of four lenses L2 a to L2d in order from the object side. The third lens group G3 consists of onelens L3 a.

Regarding the imaging lens of Example 18, Table 66 shows basic lensdata, Table 67 shows specification, Table 68 shows variable surfacedistances, Table 69 shows aspheric surface coefficients, and FIGS. 53and 54 show aberration diagrams. In FIG. 53, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.4 m (meter) from the object to the image plane Simis in focus. FIG. 54 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 66 Example 18 Sn R D Nd νd θgF  1 −633.25261 2.000 1.59551 39.240.58043  2 38.00665 12.863  3 −54.28519 1.850 1.80100 34.97 0.58642  495.00850 10.922 1.71300 53.87 0.54587  5 −67.98194 0.100  6 95.722986.765 2.00272 19.32 0.64514  7 −251.63874 1.000  8 −246.42407 6.9911.80100 34.97 0.58642  9 −53.58723 1.610 1.69895 30.13 0.60298 1099.80167 0.909 11 137.54054 10.681 1.62041 60.29 0.54266 12 −52.346512.010 1.60342 38.03 0.58356 13 −414.75790 0.100 14 143.20008 3.2251.69680 55.53 0.54341 15 366.55185 0.462 16 51.74239 6.881 1.91082 35.250.58224 17 180.97539 0.260 18 35.24471 11.944 1.81600 46.62 0.55682 19−93.14313 1.010 1.72825 28.46 0.60772 20 79.60733 0.642 21 118.005631.300 1.85896 22.73 0.62844 22 22.08603 7.000   23(St) ∞ DD[23] *24 −18.33819 1.700 1.68948 31.02 0.59874 *25  −31.12948 0.100 26 111.284515.800 1.87070 40.73 0.56825 27 −25.06585 1.220 1.69895 30.13 0.60298 28182.89249 6.206 1.81600 46.62 0.55682 29 −28.43888 DD[29] 30 −125.005631.300 1.51742 52.43 0.55649 31 ∞ 11.118 32 ∞ 2.150 1.54763 54.98 0.5524733 ∞ 1.317 34 ∞ 0.700 1.49784 54.98 0.55000 35 ∞ 1.000

TABLE 67 Example 18 f 32.025 FNo. 1.03 2ωmax 48.4

TABLE 68 Example 18 Infinity 0.4 m DD[23] 10.027 6.297 DD[29] 1.5005.230

TABLE 69 Example 18 Sn 24 25 KA 1.0000000E+00  1.0000000E+00 A47.6509788E−05  8.6420274E−05 A6 −1.2736248E−06  −6.0388926E−07 A85.0778640E−08  1.1474585E−08 A10 −1.3097284E−09  −7.5854198E−11 A122.0623870E−11 −1.6331770E−12 A14 −2.0059301E−13   3.9524334E−14 A161.1722812E−15 −3.5644909E−16 A18 −3.7566167E−18   1.5341315E−18 A205.0432936E−21 −2.6183645E−21

Example 19

FIG. 55 shows a cross-sectional configuration of the imaging lens ofExample 19. The imaging lens of Example 19 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, an aperture stop St, and a second lens group G2 that has apositive refractive power. During focusing from the object at infinityto the closest object, the first lens group G1 remains stationary withrespect to the image plane Sim, and the second lens group G2 moves tothe object side along the optical axis Z. The first lens group G1consists of twelve lenses L1 a to L1 l in order from the object side.The second lens group G2 consists of four lenses L2 a to L2 d in orderfrom the object side.

Regarding the imaging lens of Example 19, Table 70 shows basic lensdata, Table 71 shows specification, Table 72 shows variable surfacedistances, Table 73 shows aspheric surface coefficients, and FIGS. 56and 57 show aberration diagrams. In FIG. 56, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.4 m (meter) from the object to the image plane Simis in focus. FIG. 57 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 70 Example 19 Sn R D Nd νd θgF  1 −158.58566 2.000 1.56926 62.340.54137  2 45.50663 11.311  3 −58.28419 1.860 1.82401 23.80 0.61679  441.90339 13.828 1.88018 21.34 0.62618  5 −101.81510 0.100  6 98.283948.000 1.99999 15.00 0.65515  7 −127.35841 0.100  8 −132.35649 1.6001.85117 22.44 0.62166  9 84.30253 1.535 10 137.70215 12.985 1.6662858.19 0.54256 11 −39.49589 2.000 1.86788 21.61 0.62483 12 −124.454260.100 13 73.44245 7.449 1.82042 45.96 0.55588 14 −358.81915 0.000 1552.60700 4.584 1.71060 55.97 0.54269 16 93.76319 0.250 17 35.0155911.718 1.81600 46.62 0.55682 18 −112.02490 1.000 1.83429 23.29 0.6185919 45.38534 0.919 20 60.40304 1.300 1.80688 24.66 0.61389 21 21.377117.000   22(St) ∞ DD[22] 23 −24.07079 1.400 1.48001 58.75 0.54321 24352.80309 0.100 25 39.97798 8.898 1.94001 31.43 0.59353 26 −30.934421.210 1.76519 26.74 0.60732 27 59.03069 1.000 *28  53.18296 5.5001.80610 40.73 0.56940 *29  −44.23856 DD[29] 30 ∞ 2.150 1.54763 54.980.55247 31 ∞ 1.320 32 ∞ 0.700 1.49784 54.98 0.55000 33 ∞ 1.000

TABLE 71 Example 19 f 32.017 FNo. 1.03 2ωmax 49.0

TABLE 72 Example 19 Infinity 0.4 m DD[22] 10.229 5.964 DD[29] 11.83116.096

TABLE 73 Example 19 Sn 28 29 KA  1.0000000E+00 1.0000000E+00 A4−1.0078045E−05 8.8298530E−06 A6 −3.5300117E−08 −1.8081425E−07  A8−8.3277198E−10 5.3397794E−09 A10  4.3699816E−11 −9.6079166E−11  A12−7.6172757E−13 1.0902419E−12 A14  6.9072493E−15 −7.9169687E−15  A16−3.4626193E−17 3.6005727E−17 A18  9.0691746E−20 −9.3635343E−20  A20−9.6047967E−23 1.0660537E−22

Example 20

FIG. 58 shows a cross-sectional configuration of the imaging lens ofExample 20. The imaging lens of Example 20 consists of, in order fromthe object side, a first lens group G1 that has a positive refractivepower, an aperture stop St, a second lens group G2 that has a positiverefractive power, and a third lens group G3 that has a positiverefractive power. During focusing from the object at infinity to theclosest object, the first lens group G1 and the third lens group G3remain stationary with respect to the image plane Sim, and the secondlens group G2 moves to the object side along the optical axis Z. Thefirst lens group G1 consists of fourteen lenses L1 a to L1 n in orderfrom the object side. The second lens group G2 consists of four lensesL2 a to L2 d in order from the object side. The third lens group G3consists of one lens L3 a.

Regarding the imaging lens of Example 20, Table 74 shows basic lensdata, Table 75 shows specification, Table 76 shows variable surfacedistances, Table 77 shows aspheric surface coefficients, and FIGS. 59and 60 show aberration diagrams. In FIG. 59, the upper part showsaberration diagrams in a state where the object at infinity is in focus,and the lower part shows aberration diagrams in a state where the objectat the distance of 0.6 m (meter) from the object to the image plane Simis in focus. FIG. 60 shows lateral aberration diagram in a state wherethe object at infinity is in focus.

TABLE 74 Example 20 Sn R D Nd νd θgF  1 −69.40351 2.000 1.58913 61.130.54067  2 47.39750 10.135  3 −65.36696 1.860 1.85896 22.73 0.62844  4898.20220 6.892 1.88300 39.22 0.57295  5 −80.44512 0.100  6 97.489095.741 1.98613 16.48 0.66558  7 −546.89782 2.000  8 −171.12562 5.0731.88300 39.22 0.57295  9 −63.25974 1.610 1.60342 38.03 0.58356 10111.43989 1.962 11 341.07330 13.611 1.62041 60.29 0.54266 12 −34.367992.010 1.59270 35.31 0.59336 13 −113.99006 0.100 14 276.49914 3.9561.59282 68.62 0.54414 15 −272.14204 0.100 16 88.96039 4.616 1.5928268.62 0.54414 17 546.58221 0.100 18 109.73550 3.000 1.63854 55.380.54858 19 235.51602 0.000 20 32.76798 13.753 1.75500 52.32 0.54737 21−86.78027 1.010 1.74000 28.30 0.60790 22 46.97326 0.897 23 62.867691.300 1.80518 25.42 0.61616 24 24.63660 7.000   25(St) ∞ DD[25] *26 −14.19913 1.700 1.68948 31.02 0.59874 *27  −19.92300 0.100 30 217.667625.000 1.87070 40.73 0.56825 30 −32.97025 1.220 1.69895 30.13 0.60298 30−98.98873 5.691 1.88300 39.22 0.57295 31 −31.65160 DD[31] 32 300.000001.800 1.48749 70.24 0.53007 33 ∞ 11.121 34 ∞ 2.150 1.54763 54.98 0.5524735 ∞ 1.315 36 ∞ 0.700 1.49784 54.98 0.55000 37 ∞ 1.000

TABLE 75 Example 20 f 32.027 FNo. 1.03 2ωmax 49.4

TABLE 76 Example 20 Infinity 0.6 m DD[25] 11.613 8.481 DD[31] 1.5004.632

TABLE 77 Example 20 Sn 26 27 KA 1.0000000E+00 1.0000000E+00 A41.6825325E−04 1.4660302E−04 A6 −2.4177276E−06  −1.2134963E−06  A89.3324700E−08 1.6766078E−08 A10 −2.2900676E−09  1.0718903E−10 A123.4816388E−11 −8.2761040E−12  A14 −3.2819139E−13  1.3329649E−13 A161.8701820E−15 −1.0468186E−15  A18 −5.8954769E−18  4.1491271E−18 A207.8960041E−21 −6.6428045E−21 

Tables 78 to 82 show values corresponding to Conditional Expressions (1)to (19) of the imaging lenses of Examples 1 to 20. In the exampleincluding a plurality of LA positive lenses LA, values are shown for allLA positive lenses LA. In Examples 1 to 20, the d line is set as thereference wavelength. Tables 78 to 82 show the values based on the dline. ΔθgFA, ΔθgFB, and ΔθgFn1 in Tables 78 to 82 represent thefollowing values, respectively.

ΔθgFA=θgFA+0.00162×νdA−0.64159

ΔθgFB=θgFB+0.00162×νdB−0.64159

ΔθgFn1=θgFn1+0.00162×νdn1−0.64159

TABLE 78 Expression Number Example 1 Example 2 Example 3 Example 4  (1)NdA 2.00272 1.92286 1.95906 1.98613  (2) νdA 19.32 20.88 17.47 16.48 (3) νdB 90.19 81.61 68.62 68.62  (4) νdn1 19.61 18.42 21.56 21.55  (5)TL × FNo/f 2.246 2.417 2.293 2.225  (6) νdC 68.62 81.61 68.62 68.62  (7)Ndfm 1.45860 1.49700 1.59282 1.59282  (8) Ndpr 1.93784 2.00100 1.883001.88300  (9) Nd2p 1.95375 2.00100 1.88300 1.88300 (10) f1/f 2.568 2.3722.311 2.184 (11) 1/{tan(ωmax) × FNo} 3.555 3.375 3.448 3.330 (12) |f2|/f0.795 0.721 0.705 0.699 (13) f1/f2 3.231 3.288 3.281 3.122 (14) |(1 −β2²) × βr²| 0.692 0.822 0.813 0.790 (15) Tf/TL 0.544 0.576 0.547 0.534(16) f/fm 0.859 0.803 0.872 0.825 (17) ΔθgFA 0.03485 0.03124 0.046640.05069 (18) ΔθgFB 0.03968 0.02949 0.01371 0.01371 (19) ΔθgFn1 0.037180.04076 0.02842 0.02725

TABLE 79 Expression Number Example 5 Example 6 Example 7 Example 8  (1)NdA 1.89286 1.92286 2.10420 2.00069  (2) νdA 20.36 18.90 17.02 25.46 (3) νdB 67.73 74.70 94.66 75.50  (4) νdn1 23.02 22.62 20.89 24.40  (5)TL × FNo/f 2.230 2.443 2.660 2.262  (6) νdC 67.73 74.70 94.66 75.50  (7)Ndfm 1.59522 1.53775 1.43875 1.55032  (8) Ndpr 1.90043 1.85067 1.847861.86725  (9) Nd2p 1.90043 1.85067 1.84786 1.86725 (10) f1/f 2.366 2.0032.051 2.513 (11) 1/{tan(ωmax) × FNo} 3.462 3.329 3.279 3.512 (12) |f2|/f0.684 0.715 0.730 0.661 (13) f1/f2 3.457 2.800 2.808 3.800 (14) |(1 −β2²) × βr²| 0.821 0.751 0.762 0.842 (15) Tf/TL 0.540 0.589 0.620 0.550(16) f/fm 0.860 0.822 0.796 0.933 (17) ΔθgFA 0.03083 0.03863 0.049090.01330 (18) ΔθgFB 0.01239 0.01878 0.04578 0.02073 (19) ΔθgFn1 0.020680.01986 0.02360 0.01811

TABLE 80 Expression Number Example 9 Example 10 Example 11 Example 12 (1) NdA 1.92119 2.05090 1.95375 1.92119  (2) νdA 23.96 26.94 32.3223.96  (3) νdB 81.61 68.62 94.66 75.50  (4) νdn1 23.02 22.73 27.01 24.10 (5) TL × FNo/f 2.244 2.709 2.685 2.740  (6) νdC 81.61 68.62 90.19 67.73 (7) Ndfm 1.49700 1.56883 1.43875 1.55032  (8) Ndpr 1.88300 1.736301.82897 1.78517  (9) Nd2p 1.88300 1.79841 1.93835 1.83756 (10) f1/f2.380 0.872 1.076 1.050 (11) 1/{tan(ωmax) × FNo} 3.482 3.302 3.395 3.309(12) |f2|/f 0.679 0.583 0.851 0.786 (13) f1/f2 3.503 — — — (14) |(1 −β2²) × βr²| 0.823 1.294 0.821 0.875 (15) Tf/TL 0.546 0.285 0.335 0.339(16) f/fm 0.856 — 0.925 0.955 (17) ΔθgFA 0.01748 0.00724 0.00092 0.01748(18) ΔθgFB 0.02949 0.01371 0.04578 0.02073 (19) ΔθgFn1 0.02068 0.023670.01127 0.01848

TABLE 81 Expression Number Example 13 Example 14 Example 15 Example 16 (1) NdA 2.00069 2.00001 2.00001 2.10420 1.95906 1.99166 1.98542 1.92286— 2.00001 2.00000 —  (2) νdA 25.46 16.35 16.89 17.02 17.47 26.42 25.7920.88 — 15.00 15.00 —  (3) νdB 94.66 94.66 94.66 60.47  (4) νdn1 26.8722.80 24.57 22.14  (5) TL × FNo/f 4.077 4.677 4.548 4.012  (6) νdC 81.5467.73 67.73 —  (7) Ndfm 1.43875 1.43875 1.43875 1.59410  (8) Ndpr1.84950 1.64162 1.82040 1.79175  (9) Nd2p 1.81272 1.71964 1.806921.81305 (10) f1/f 3.011 2.883 2.441 2.818 (11) 1/{tan(ωmax) × FNo} 2.1321.939 2.021 2.248 (12) |f2|/f 1.395 1.501 1.493 1.281 (13) f1/f2 2.1581.921 1.634 2.200 (14) |(1 − β2²) × βr²| 0.890 0.880 0.832 0.900 (15)Tf/TL 0.696 0.713 0.713 0.691 (16) f/fm 0.589 0.588 0.630 0.689 (17)ΔθgFA 0.01330 0.03483 0.03363 0.04909 0.04664 0.01225 0.01358 0.03124 —0.03786 0.03786 — (18) ΔθgFB 0.04578 0.04578 0.04578 0.01153 (19) ΔθgFn10.02590 0.01910 0.01733 0.03186

TABLE 82 Expression Number Example 17 Example 18 Example 19 Example 20 (1) NdA 2.00069 2.00272 1.88018 1.98613 1.95906 — 1.99999 —  (2) νdA25.46 19.32 21.34 16.48 17.47 — 15.00 —  (3) νdB 94.66 60.29 58.19 68.62 (4) νdn1 26.43 25.60 22.03 24.08  (5) TL × FNo/f 4.728 4.324 4.3104.269  (6) νdC 68.62 — — 68.62  (7) Ndfm 1.43875 1.62041 1.66628 1.59282 (8) Ndpr 1.87685 1.84335 1.87306 1.74707  (9) Nd2p 1.82640 1.843351.87306 1.87685 (10) f1/f 2.675 1.780 1.921 1.685 (11) 1/{tan(ωmax) ×FNo} 2.127 2.145 2.132 2.107 (12) |f2|/f 1.611 0.985 1.099 1.208 (13)f1/f2 1.660 1.806 1.748 1.395 (14) |(1 − β2²) × βr²| 0.860 0.822 0.7290.595 (15) Tf/TL 0.705 0.677 0.669 0.669 (16) f/fm — — — — (17) ΔθgFA0.01330 0.03485 0.01916 0.05069 0.04664 — 0.03786 — (18) ΔθgFB 0.04578−0.00126 −0.00476 0.01371 (19) ΔθgFn1 0.01694 0.01795 0.01734 0.01971

The F numbers of the imaging lenses of Examples 1 to 20 are smaller than2. In particular, the F numbers of the imaging lenses of Examples 1 to 9are smaller than 1.2. The imaging lens of Examples 1 to 20 have such asmall F number, reduction in size is achieved, and various aberrationsare satisfactorily corrected, whereby high optical performance isachieved.

Next, an imaging apparatus according to an embodiment of the presentdisclosure will be described. FIGS. 61 and 62 are external views of acamera 30 which is the imaging apparatus according to the embodiment ofthe present disclosure. FIG. 61 is a perspective view of the camera 30viewed from the front side, and FIG. 62 is a perspective view of thecamera 30 viewed from the rear side. The camera 30 is a so-calledmirrorless type digital camera, and the interchangeable lens 20 can bedetachably attached thereto. The interchangeable lens 20 includes theimaging lens 1, which is housed in a lens barrel, according to anembodiment of the present disclosure.

The camera 30 comprises a camera body 31, and a shutter button 32 and apower button 33 are provided on an upper surface of the camera body 31.Further, an operation section 34, an operation section 35, and a displaysection 36 are provided on a rear surface of the camera body 31. Thedisplay section 36 displays a captured image and an image within anangle of view before imaging.

An imaging aperture, through which light from an imaging target isincident, is provided at the center on the front surface of the camerabody 31. A mount 37 is provided at a position corresponding to theimaging aperture. The interchangeable lens 20 is mounted on the camerabody 31 with the mount 37 interposed therebetween.

In the camera body 31, there are provided an imaging element, a signalprocessing circuit, a storage medium, and the like. The imaging elementsuch as a charge coupled device (CCD) or a complementary metal oxidesemiconductor (CMOS) outputs a captured image signal based on a subjectimage which is formed through the interchangeable lens 20. The signalprocessing circuit generates an image through processing of the capturedimage signal which is output from the imaging element. The storagemedium stores the generated image. The camera 30 is able to capture astill image or a video by pressing the shutter button 32, and is able tostore image data, which is obtained through imaging, in the storagemedium.

The technology of the present disclosure has been hitherto describedthrough embodiments and examples, but the technology of the presentdisclosure is not limited to the above-mentioned embodiments andexamples, and may be modified into various forms. For example, valuessuch as the radius of curvature, the surface distance, the refractiveindex, the Abbe number, and the aspheric surface coefficient of eachlens are not limited to the values shown in the numerical examples, anddifferent values may be used therefor.

Further, the imaging apparatus according to the embodiment of thepresent disclosure is not limited to the above example, and may bemodified into various forms such as a camera other than the mirrorlesstype, a film camera, and a video camera.

What is claimed is:
 1. An imaging lens comprising, as lens groups,successively in order from a position closest to an object side to animage side: a first lens group that has a positive refractive power; anda second lens group that has a refractive power, wherein duringfocusing, a distance between the first lens group and the second lensgroup changes, and mutual distances between all lenses in the first lensgroup and mutual distances between all lenses in the second lens groupare constant, a stop is disposed closer to the image side than a lenswhich is second from the object side, a combined refractive power of alllenses closer to the object side than the stop is positive, at least oneLA positive lens and at least one LB positive lens are provided closerto the object side than the stop, an Abbe number of the LB positive lensbased on a d line is a maximum of Abbe numbers of all the positivelenses closer to the object side than the stop based on the d line,assuming that a refractive index of the LA positive lens at the d lineis NdA, an Abbe number of the LA positive lens based on the d line isνdA, and the Abbe number of the LB positive lens based on the d line isνdB, Conditional Expressions (1), (2), and (3) are satisfied, which arerepresented by1.86<NdA<2.2  (1),10<νdA<35  (2), and57<νdB<105  (3).
 2. The imaging lens according to claim 1, wherein thefirst lens group includes at least two positive lenses and at least twonegative lenses.
 3. The imaging lens according to claim 1, wherein thesecond lens group includes at least two positive lenses and at least twonegative lenses.
 4. The imaging lens according to claim 1, wherein thefirst lens group remains stationary with respect to an image plane andthe second lens group moves during focusing.
 5. The imaging lensaccording to claim 1, wherein only one lens group moves during focusing.6. The imaging lens according to claim 5, wherein the only lens groupthat moves during focusing is the second lens group.
 7. The imaging lensaccording to claim 1, wherein the first lens group includes at least twonegative lenses, and assuming that an average value of Abbe numbers oftwo negative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, Conditional Expression (4) is satisfied, which is represented by15<νdn1<28  (4).
 8. The imaging lens according to claim 1, whereinduring focusing, the first lens group remains stationary with respect toan image plane, and the first lens group includes at least one LApositive lens.
 9. The imaging lens according to claim 1, whereinassuming that a sum of a distance on an optical axis from a lens surfaceclosest to the object side to a lens surface closest to the image sideand a back focal length at an air-converted distance in a state where anobject at infinity is in focus is TL, an F number of the imaging lens inthe state where the object at infinity is in focus is FNo, and a focallength of the imaging lens in the state where the object at infinity isin focus is f, Conditional Expression (5) is satisfied, which isrepresented by1.5<TL×FNo/f<5  (5).
 10. The imaging lens according to claim 1,comprising, in order from the object side to the image side, as lensgroups, only two lens groups consisting of the first lens group thatremains stationary with respect to an image plane during focusing andthe second lens group that moves during focusing, or comprising, inorder from the object side to the image side, as lens groups, only threelens groups consisting of the first lens group that remains stationarywith respect to the image plane during focusing, the second lens groupthat moves during focusing, and a third lens group that consists of twoor less lenses and remains stationary with respect to the image planeduring focusing.
 11. The imaging lens according to claim 1, wherein thesecond lens group is a lens group having a positive refractive power.12. The imaging lens according to claim 1, wherein the first lens groupincludes at least three negative lenses.
 13. The imaging lens accordingto claim 1, wherein the second lens group includes at least two positivelenses and at least three negative lenses.
 14. The imaging lensaccording to claim 1, wherein in a case where one lens component is onesingle lens or one cemented lens, in the lens component closest to theobject side and the lens component which is second from the object side,one lens component has a negative refractive power and the other lenscomponent has a positive refractive power, and on-axis ray emitted froma lens surface closest to the image side in the one lens componenthaving a negative refractive power to the image side in a state where anobject at infinity is in focus is divergent light.
 15. The imaging lensaccording to claim 1, wherein at least one of the lens closest to theobject side or a lens which is second from the object side is a negativelens of which the object side lens surface has a concave shape.
 16. Theimaging lens according to claim 1, wherein the lens closest to theobject side is a negative lens.
 17. The imaging lens according to claim1, comprising, successively in order from the position closest to theobject side: a single lens that has a negative refractive power, asingle lens that has a positive refractive power, and a single lens thathas a positive refractive power.
 18. The imaging lens according to claim1, wherein an object side lens surface of the lens closest to the objectside has a concave shape.
 19. The imaging lens according to claim 1,comprising at least one LC positive lens closer to the object side thanthe stop, wherein the LC positive lens is a positive lens having amaximum or second largest Abbe number based on the d line among allpositive lenses closer to the object side than the stop, and assumingthat the Abbe number of the LC positive lens based on the d line is νdC,Conditional Expression (6) is satisfied, which is represented by57<νdC<102  (6).
 20. The imaging lens according to claim 1, whereinassuming that a minimum value of refractive indexes of all positivelenses closer to the object side than the stop at the d line is Ndfm,Conditional Expression (7) is satisfied, which is represented by1.46<Ndfm<1.72  (7).
 21. The imaging lens according to claim 1, whereinthe stop is disposed in a lens group which remains stationary withrespect to an image plane during focusing, or the stop is disposedbetween the lens groups.
 22. The imaging lens according to claim 1,wherein the stop is disposed between the first lens group and the secondlens group, and the first lens group and the stop remain stationary withrespect to an image plane and the second lens group moves duringfocusing.
 23. The imaging lens according to claim 1, wherein duringfocusing, the second lens group moves, and the number of lenses includedin the second lens group is seven or less.
 24. The imaging lensaccording to claim 1, wherein during focusing, the second lens groupmoves, and the number of lenses included in the second lens group is sixor less.
 25. The imaging lens according to claim 1, wherein duringfocusing, the second lens group moves, and the number of lenses includedin the second lens group is five or less.
 26. The imaging lens accordingto claim 1, wherein the number of lenses disposed closer to the objectside than the stop is eight or less.
 27. The imaging lens according toclaim 1, wherein the number of lenses disposed closer to the object sidethan the stop is seven or less.
 28. The imaging lens according to claim1, wherein the number of lenses included in the imaging lens is thirteenor less.
 29. The imaging lens according to claim 1, wherein the numberof lenses included in the imaging lens is twelve or less.
 30. Theimaging lens according to claim 1, comprising at least two positivelenses closer to the image side than the stop, wherein assuming that anaverage value of refractive indexes of all positive lenses closer to theimage side than the stop at the d line is Ndpr, Conditional Expression(8) is satisfied, which is represented by1.77<Ndpr<2.15  (8).
 31. The imaging lens according to claim 1, whereinduring focusing, the second lens group moves, and the second lens groupincludes at least one positive lens, and assuming that an average valueof refractive indexes of all the positive lenses in the second lensgroup at the d line is Nd2p, Conditional Expression (9) is satisfied,which is represented by1.7<Nd2p<2.2  (9).
 32. The imaging lens according to claim 1, whereinduring focusing, the second lens group moves, and the second lens groupincludes at least two cemented lenses.
 33. The imaging lens according toclaim 1, wherein three positive lenses are successively arranged in thefirst lens group.
 34. The imaging lens according to claim 1, whereinfour positive lenses are successively arranged in the first lens group.35. The imaging lens according to claim 1, assuming that a focal lengthof the first lens group is f1, and a focal length of the imaging lens inthe state where the object at infinity is in focus is f, ConditionalExpression (10) is satisfied, which is represented by0.5<f1/f<3.5  (10).
 36. The imaging lens according to claim 1, whereinassuming that a maximum half angle of view of the imaging lens in astate where an object at infinity is in focus is ω max, and an F numberof the imaging lens in the state where the object at infinity is infocus is FNo, Conditional Expression (11) is satisfied, which isrepresented by1.8<1/{tan(ω max)×FNo}<4.5  (11).
 37. The imaging lens according toclaim 1, wherein during focusing, the second lens group moves, andassuming a focal length of the second lens group is f2, and a focallength of the imaging lens in the state where the object at infinity isin focus is f, Conditional Expression (12) is satisfied, which isrepresented by0.3<|f2|/f<2.2  (12).
 38. The imaging lens according to claim 1, whereinassuming that a focal length of the first lens group is f1, and a focallength of the second lens group is f2, Conditional Expression (13) issatisfied, which is represented by1<f/f2<5  (13).
 39. The imaging lens according to claim 1, whereinduring focusing, the second lens group moves, and assuming that alateral magnification of the second lens group in a state where anobject at infinity is in focus is β2, and a combined lateralmagnification of all lenses closer to the image side than the secondlens group in the state where the object at infinity is in focus is βrin a case where a lens is disposed closer to the image side than thesecond lens group, and βr is set to 1 in a case where no lens isdisposed closer to the image side than the second lens group,Conditional Expression (14) is satisfied, which is represented by0.3<|(1−β2²)×βr ²|<1.5  (14).
 40. The imaging lens according to claim 1,wherein assuming that a distance on an optical axis from a lens surfaceclosest to the object side to the stop in a state where an object atinfinity is in focus is Tf, and a sum of a distance on an optical axisfrom a lens surface closest to the object side to a lens surface closestto the image side and a back focal length at an air-converted distancein the state where the object at infinity is in focus is TL, ConditionalExpression (15) is satisfied, which is represented by0.2<Tf/TL<0.65  (15).
 41. The imaging lens according to claim 1, whereinthe first lens group includes, successively in order from the positionclosest to the object side, a first unit which has a negative refractivepower and a second unit which is separated from the first unit by amaximum air distance on an optical axis in the first lens group and hasa positive refractive power, the second unit consists of one single lensor one cemented lens, and assuming that a focal length of the imaginglens in a state where an object at infinity is in focus is f, and acombined focal length of all lenses closer to the image side than thesecond unit of the imaging lens in the state where the object atinfinity is in focus is fm, Conditional Expression (16) is satisfied,which is represented by0.7<f/fm<0.98  (16).
 42. The imaging lens according to claim 41, whereinthe first unit consists of one negative lens, and the second unitconsists of one positive lens.
 43. The imaging lens according to claim1, wherein assuming that a partial dispersion ratio between a g line andan F line of the LA positive lens is θgFA, Conditional Expression (17)is satisfied, which is represented by0.01<θgFA+0.00162×νdA−0.64159<0.06  (17).
 44. The imaging lens accordingto claim 1, assuming that a partial dispersion ratio of the LB positivelens between a g line and an F line is θgFB, Conditional Expression (18)is satisfied, which is represented by0.01<θgFB+0.00162×νdB−0.64159<0.05  (18).
 45. The imaging lens accordingto claim 1, wherein the first lens group includes at least two negativelenses, and assuming that an average value of Abbe numbers of twonegative lenses based on the d lines is νdn1 where the two negativelenses are selected from negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, and an average value of partial dispersion ratios of two negativelenses between a g line and an F line is θgFn1 where the two negativelenses are selected from the negative lenses having smaller Abbe numbersbased on the d line among the negative lenses included in the first lensgroup, Conditional Expression (19) is satisfied, which is represented by0.01<θgFn1+0.00162×νdn1−0.64159<0.05  (19).
 46. The imaging lensaccording to claim 1, wherein Conditional Expression (1-1) is satisfied,which is represented by1.88<NdA<2.15  (1-1).
 47. The imaging lens according to claim 1, whereinConditional Expression (2-1) is satisfied, which is represented by13.5<νdA<31  (2-1).
 48. The imaging lens according to claim 1, whereinConditional Expression (3-1) is satisfied, which is represented by62<νdB<92  (3-1).
 49. The imaging lens according to claim 7, whereinConditional Expression (4-1) is satisfied, which is represented by16<νdn1<25  (4-1).
 50. An imaging apparatus comprising the imaging lensaccording to claim 1.